### Tamilnadu Board Physics Question papers for 12th Standard (English Medium) Question paper & Study Materials

#### 12th Standard English Medium Physics Reduced syllabus Annual Exam Model Question Paper with Answer key - 2021 - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 3)

The relative permittivity of water is _______.

• 4)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 5)

In a large building, there are 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80W and 1 heater of 1kW are connected. The voltage of electric mains is 220V. The minimum capacity of the main fuse of the building will be

#### 12th Standard English Medium Physics Reduced syllabus Annual Exam Model Question Paper - 2021 - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

Rank the electrostatic potential energies for the given system of charges in increasing order.

• 3)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 4)

Th e following graph shows current versus voltage values of some unknown conductor. What is the resistance of this conductor?

• 5)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

#### 12th Standard English Medium Physics Reduced syllabus Public Exam Model Question Paper with Answer key - 2021 - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 2)

Rank the electrostatic potential energies for the given system of charges in increasing order.

• 3)

Two metallic spheres of radii 1 cm and 3 cm are given charges of -1 x 10-2 C and 5 x 10-2 C respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is

• 4)

There is a current of 1.0 A in the circuit shown below. What is the resistance of P ?

• 5)

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

#### 12th Standard English Medium Physics Reduced syllabus Public Exam Model Question Paper - 2021 - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 2)

Two metallic spheres of radii 1 cm and 3 cm are given charges of -1 x 10-2 C and 5 x 10-2 C respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is

• 3)

_______ and Coulomb's law form fundamental principles of electrostatics

• 4)

The electric potential V as a function of distance x (metres) is given by V = ( 5x2 + 10x -9) volt. The value of electric field at a point x = 1m is

• 5)

At Infinity (i.e r = ∞), the electrostatic potential (V) is

#### 12th Standard English Medium Physics Reduced syllabus Creative Five mark Question with Answerkey - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 2)

A wire of resistance 2 ohms per meter is bent to form a circle of radius 1m. Th e equivalent resistance between its two diametrically opposite points, A and B as shown in the fi gure is

• 3)

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

• 4)

Th e force experienced by a particle having mass m and charge q accelerated through a potential diff erence V when it is kept under perpendicular magnetic field $\vec { B }$ is

• 5)

The BH curve for a ferromagnetic material is shown in the figure. The material is placed inside a long solenoid which contains 1000 turns/cm. The current that should be passed in the solenonid to demagnetize the ferromagnet completely is

#### 12th Standard English Medium Physics Reduced syllabus Creative Three mark Question with Answerkey - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

Define potential difference and derive.

• 2)

Derive an expression for electric flus in a non uniform electric field and an arbitrarily shaped area.

• 3)

What is dielectrics or insulators.

• 4)

(a) Distinguish between electric cells and batteries.
(b) Explain its function

• 5)

Find the expression for the equivalent emf & internal resistance of the series combination of cells

#### 12th Standard English Medium Physics Reduced syllabus Creative two mark Question with Answerkey - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

When does a dielectric said to be polarized?

• 2)

What is the electric flux through a cube of side 1cm which encloses on electric dipole?

• 3)

What orientation of an electric dipole in a uniform electric field corresponds to its
(i) stable and
(ii) unstable equilibrium? Depict the orientations.

• 4)

Two isolated metal spheres A &B have radii R & 2R respectively and same charge q. Find which of the two spheres have greater energy density just outside the surface of the sphere.

• 5)

The electric field due to a point charge depends on the distance r as parallely indicate how each of the following quantities depends on r?
a. Intensity of light from a point source.
b. Electrical potential due to a point charge.
c. Electrical potential at a distance r from to centre of a charged metallic sphere Given r < radius of the sphere.

#### 12th Standard English Medium Physics Reduced syllabus Creative one mark Question with Answerkey - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

The torque experienced by a rectangular current loop placed perpendicular to a uniform magnetic field is

• 2)

Lenz's law is in accordance with the law of

• 3)

The efficiency of an ideal transformer is

• 4)

The average power consumed per cycle is:

• 5)

An object is placed at 20 cm from a convex mirror of focal length 10 cm. The image formed by the mirror is

#### 12th Standard English Medium Physics Reduced syllabus Five mark important Questions with Answer key - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

A parallel plate capacitor has square plates of side 5 cm and separated by a distance of 1 mm.
(a) Calculate the capacitance of this capacitor.
(b) If a 10 V battery is connected to the capacitor, what is the charge stored in any one of the plates? (The value of εo = 8.85 x 10-12 Nm2 C-2)

• 2)

Dielectric strength of air is 3 × 106 V m-1. Suppose the radius of a hollow sphere in the Van de Graff generator is R = 0.5 m, calculate the maximum potential difference created by this Van de Graaff generator.

• 3)

Five identical charges Q are placed equidistant on a semicircle as shown in the figure. Another point charge q is kept at the center of the circle of radius R. Calculate the electrostatic force experienced by the charge q.

• 4)

The electrostatic potential is given as a function of x in figure (a) and (b). Calculate the corresponding electric fields in regions A, B, C and D. Plot the electric field as a function of x for the figure (b).

• 5)

A battery of voltage V is connected to 30 W bulb and 60 W bulb as shown in the figure. (a) Identify brightest bulb (b) which bulb has greater resistance?
(c) Suppose the two bulbs are connected in series, which bulb will glow brighter?

#### 12th Standard English Medium Physics Reduced syllabus Five mark important Questions - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

A water molecule has an electric dipole moment of 6.3 × 10-30 Cm. A sample contains 1022 water molecules, with all the dipole moments aligned parallel to the external electric field of magnitude 3 × 105 NC-1. How much work is required to rotate all the water molecules from θ = 00 to 900?

• 2)

A small ball of conducting material having a charge +q and mass m is thrown upward at an angle θ to horizontal surface with an initial speed vo as shown in the figure. There exists an uniform electric field E downward along with the gravitational field g. Calculate the range, maximum height and time of flight in the motion of this charged ball. Neglect the effect of air and treat the ball as a point mass.

• 3)

Suppose a charge +q on Earth’s surface and another +q charge is placed on the surface of the Moon. (a) Calculate the value of q required to balance the gravitational attraction between Earth and Moon (b) Suppose the distance between the Moon and Earth is halved, would the charge q change?
(Take mE = 5.9 × 1024 kg, mM = 7.9 × 1022 kg)

• 4)

A point charge of +10 μC is placed at a distance of 20 cm from another identical point charge of +10 μC. A point charge of -2 μC is moved from point a to b as shown in the figure. Calculate the change in potential energy of the system? Interpret your result.

• 5)

For the given capacitor configuration
(a) Find the charges on each capacitor
(b) potential difference across them
(c) energy stored in each capacitor

#### 12th Standard English Medium Physics Reduced syllabus Three mark important Questions with Answer key - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

Calculate the electrostatic force and gravitational force between the proton and the electron in a hydrogen atom. They are separated by a distance of 5.3 × 10-11 m. The magnitude of charges on the electron and proton are 1.6 × 10-19 C. Mass of the electron is me = 9.1 × 10-31 kg and mass of proton is mp = 1.6 × 10-27 kg.

• 2)

Consider the charge configuration as shown in the figure. Calculate the electric field at point A. If an electron is placed at points A, what is the acceleration experienced by this electron? (mass of the electron = 9.1 × 10-31 kg and charge of electron = −1.6 × 10-19 C)

• 3)

A sample of HCl gas is placed in a uniform electric field of magnitude 3 × 104 NC-1. The dipole moment of each HCl molecule is 3.4 × 10-30 Cm. Calculate the maximum torque experienced by each HCl molecule.

• 4)

Obtain the expression for energy stored in the parallel plate capacitor.

• 5)

Explain in detail how charges are distributed in a conductor, and the principle behind the lightning conductor.

#### 12th Standard English Medium Physics Reduced syllabus Three mark important Questions - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

Calculate the number of electrons in one coulomb of negative charge.

• 2)

Calculate the electrostatic force and gravitational force between the proton and the electron in a hydrogen atom. They are separated by a distance of 5.3 × 10-11 m. The magnitude of charges on the electron and proton are 1.6 × 10-19 C. Mass of the electron is me = 9.1 × 10-31 kg and mass of proton is mp = 1.6 × 10-27 kg.

• 3)

The following pictures depict electric field lines for various charge configurations.

(i) In figure (a) identify the signs of two
charges and find the ratio $\left| \frac { { q }_{ 1 } }{ { q }_{ 2 } } \right|$
(ii) In figure (b), calculate the ratio of two positive charges and identify the strength of the electric field at three points A, B, and C
(iii) Figure (c) represents the electric field lines for three charges. If q2 = -20 nC, then calculate the values of q1 and q3.

• 4)

Define ‘Electric field’ and discuss its various aspects.

• 5)

Obtain an expression for potential energy due to a collection of three point charges which are separated by finite distances.

#### 12th Standard English Medium Physics Reduced syllabus Two mark important Questions with Answer key - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

Define ‘electrostatic potential energy’.

• 2)

What are Non-polar molecules

• 3)

What is dielectric breakdown.

• 4)

What is the electric flux through a cube of side 1cm which encloses on electric dipole?

• 5)

A particle of mass m and charge (-q) enters the region between the two charged plates initrally moving along X-axis with speed Vx as shown in figure. The length of plate is L and an uniform electric field E is maintained between the plates. S.T. vertical deflection of the particle at the far edge of the plate is $\frac { q{ EL }^{ 2 } }{ 2m{ V }_{ x }^{ 2 } }$.

#### 12th Standard English Medium Physics Reduced syllabus Two mark important Questions - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

What is meant by quantisation of charges?

• 2)

Define ‘Electric field’.

• 3)

(i) Two insulated charged copper spheres A & B of identical size have charges qn and -3qA respectively. When they are brought in contact with each other and then separated. What are the new charges on them?
(ii) When third sphere of some size but uncharged is brought in contact with first and then second and finally removed? What are the new charges.

• 4)

A charge Q μc is placed at the centre of a cube what would be the
(i) flux through one face?
(ii) flux passing through two opposite faces of the cube?
Electric flux through whole cube $\frac { Q }{ { \varepsilon }_{ 0 } }$

• 5)

Represent the variation of electric field due to point charge Q with
a) magnitude of charge Q
b) r and
c) $\frac{1}{r^2}$ where r is the distance of the observation point from the charge. graphically.

#### 12th Standard English Medium Physics Reduced syllabus One mark important Questions with Answer key - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 2)

The value of constant 'K' in coulomb law is

• 3)

Two charges are kept at a distance in air what should be the relative permittivity of the medium in which the two charges should be kept at the same distance so that they experience half of the force which they experienced in air?

• 4)

In a parallel plate capacitor of capacitance C, a metal sheet is inserted between the plates, parallel to them. The thickness of the sheet is half of the separation between the plates. The capacitance now becomes

• 5)

During charging a capacitor variation of potential V of the capacitor with time t as shown a

#### 12th Standard English Medium Physics Reduced syllabus One mark important Questions - 2021(Public Exam ) - by Sarojini - Tiruppur - Feb 27, 2021 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 3)

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric fl ux through each Gaussian surface in increasing order.

• 4)

Rank the electrostatic potential energies for the given system of charges in increasing order.

• 5)

If voltage applied on a capacitor is increased from V to 2V, choose the correct conclusion

#### 12th Standard Physics English Medium Recent developments in Physics Reduced Syllabus Important Questions With Answer Key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

The particle size of ZnO material is 30 nm. Based on the dimension it is classified as

• 2)

The blue print for making ultra durable synthetic material is mimicked from

• 3)

The alloys used for muscle wires in Robots are

• 4)

The technology used for stopping the brain from processing pain is

• 5)

The particle which gives mass to protons and neutrons are

#### 12th Standard Physics English Medium Recent developments in Physics Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

The particle size of ZnO material is 30 nm. Based on the dimension it is classified as

• 2)

The blue print for making ultra durable synthetic material is mimicked from

• 3)

The materials used in Robotics are

• 4)

The alloys used for muscle wires in Robots are

• 5)

The technology used for stopping the brain from processing pain is

#### 12th Standard Physics English Medium Electronics and Communication Systems Reduced Syllabus Important Questions With Answer Key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

Doping a semiconductor results in

• 2)

The output transducer of the communication system converts the radio signal into ________.

• 3)

The forbidden energy band gap in semi conductor, conductor and insulator are E1, E2 and E3 respectively. The relation among them is

• 4)

The radiation of electrical energy is practicable only above _________

• 5)

Microphone converts __________ energy into ________ energy.

#### 12th Standard Physics English Medium Electronics and Communication Systems Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

The output transducer of the communication system converts the radio signal into ________.

• 2)

Which of the following is not the advantage of PN junction diode over tube value?

• 3)

In a N-P-N transistor circuit, the emitter, collector and base current are respectively IE, IC and lB. The relation between them is

• 4)

From the follwoing semi-conductor devices _________ operates in forward bias only.

• 5)

To obtain a p-type germanium semiconductor, it must be doped with

#### 12th Standard Physics English Medium Atomic and nuclear Physics Reduced Syllabus Important Questions With Answer Key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

In a hydrogen atom, the electron revolving in the fourth orbit, has angular momentum equal to

• 2)

The electric potential between a proton and an electron is given by $V={ V }_{ 0 }in\left( \frac { r }{ { r }_{ 0 } } \right)$, where r0 is a constant. Assume that Bohr atom model is applicable of nth orbit rn with the principal quantum number n is

• 3)

The fig. represents the observed intensity of X-rays emitted by an X-ray tube as a function of wavelength. The sharp peaks A and B denote

• 4)

A beam of electron posses undeflected through mutually perpendicular electric and magnetic fields. If the electric field is switched off and the same magnetic field is maintained, the electrons move,

• 5)

The energy of a photon of characteristic X-ray from a Coolidge tubes comes from

#### 12th Standard Physics English Medium Atomic and nuclear Physics Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

Suppose an alpha particle accelerated by a potential of V volt is allowed to collide with a nucleus whose atomic number is Z, then the distance of closest approach of alpha particle to the nucleus is

• 2)

The electric potential between a proton and an electron is given by $V={ V }_{ 0 }in\left( \frac { r }{ { r }_{ 0 } } \right)$, where r0 is a constant. Assume that Bohr atom model is applicable of nth orbit rn with the principal quantum number n is

• 3)

An oil drop carrying a charge q has a mass m kg. It is falling freely in air with terminal speed v. The electric field required to make the drop move upwards with the same speed is

• 4)

When hydrogen atom is in its first excited level, its radius is __________ of the Bohr radius.

• 5)

J.J. Thomson's experiment demonstrated that

#### 12th Standard Physics English Medium Dual Nature of Radiation and Matter Reduced Syllabus Important Questions With Answer Key 20211 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

The wavelength λe of an electron and λp of a photon of same energy E are related by

• 2)

If a light of wavelength 330 nm is incident on a metal with work function 3.55 eV, the electrons are emitted. Then the wavelength of the emitted electron is (Take h = 6.6 × 10–34 Js)

• 3)

A photoelectric surface is illuminated successively by monochromatic light of wavelength λ and $\frac{\lambda}{2}.$ If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the fi rst case, the work function at the surface of material is

• 4)

The threshold wavelength for a metal surface whose photoelectric work function is 3.313 eV is

• 5)

Emission of electrons by the absorption of heat energy is called_______emission.

#### 12th Standard Physics English Medium Dual Nature of Radiation and Matter Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

The wavelength λe of an electron and λp of a photon of same energy E are related by

• 2)

In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would

• 3)

A particle of mass 3 × 10–6 g has the same wavelength as an electron moving with a velocity 6 10 × 6m s−1. The velocity of the particle is

• 4)

Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is

• 5)

The work functions for metals A, B and C are 1.92 eV, 2.0 eV and 5.0 eV respectively. The metals which will emit photoelectrons for a radiation of wavelength 4100$\\ \\ \mathring { A } \\$ is/are

#### 12th Standard Physics English Medium Wave Optics Reduced Syllabus Important Questions With Answer Key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

A plane glass is placed over a various coloured letters (violet, green, yellow, red) The letter which appears to be raised more is,

• 2)

In a Young’s double-slit experiment, the slit separation is doubled. To maintain the same fringe spacing on the screen, the screen-to-slit distance D must be changed to,

• 3)

Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are

• 4)

When light is incident on a soap film of thickness 5×10–5 cm, the wavelength of light reflected maximum in the visible region is 5320 Å. Refractive index of the film will be,

• 5)

First diffraction minimum due to a single slit of width 1.0×10–5 cm is at 30o. Then wavelength of light used is,

#### 12th Standard Physics English Medium Wave Optics Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

A plane glass is placed over a various coloured letters (violet, green, yellow, red) The letter which appears to be raised more is,

• 2)

In a Young’s double-slit experiment, the slit separation is doubled. To maintain the same fringe spacing on the screen, the screen-to-slit distance D must be changed to,

• 3)

Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are

• 4)

When light is incident on a soap film of thickness 5×10–5 cm, the wavelength of light reflected maximum in the visible region is 5320 Å. Refractive index of the film will be,

• 5)

First diffraction minimum due to a single slit of width 1.0×10–5 cm is at 30o. Then wavelength of light used is,

#### 12th Standard Physics English Medium Ray Optics Reduced Syllabus Important Questions With Answer Key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

An object is placed in front of a convex mirror of focal length of f and the maximum and minimum distance of an object from the mirror such that the image formed is real and magnified.

• 2)

For light incident from air on a slab of refractive index 2, the maximum possible angle of refraction is,

• 3)

A plane glass is placed over a various coloured letters (violet, green, yellow, red) The letter which appears to be raised more is,Two point white dots are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm approximately. The maximum distance at which these dots can be resolved by the eye is, [take wavelength of light, λ = 500 nm]

• 4)

A light bulb is placed between two mirrors (plane) inclined at an angle of 60°. Number of images formed are

• 5)

A man of length h requires a mirror of length at least equal to, to see his own complete image

#### 12th Standard Physics English Medium Ray Optics Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

The speed of light in an isotropic medium depends on,

• 2)

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index,

• 3)

A ray of light travelling in a transparent medium of refractive index n falls, on a surface separating the medium from air at an angle of incidents of 45o. The ray can undergo total internal reflection for the following n,

• 4)

The light reflected by plane mirror may form a real images.

• 5)

Ray optics is valid, when characteristic dimensions are

#### 12th Standard Physics English Medium Electromagnetic Waves Reduced Syllabus Important Questions With Answer Key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

If the magnetic monopole exists, then which of the Maxwell’s equation to be modified?.

• 2)

Who produced the electromagnetic waves first?

• 3)

The existence of E.M. waves was confirmed experimentally by

• 4)

Electromagnetic waves are discovered by

• 5)

Cellular phones use radio frequencies in

#### 12th Standard Physics English Medium Electromagnetic Waves Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

If the magnetic monopole exists, then which of the Maxwell’s equation to be modified?.

• 2)

The phase and orientation of the magnetic vector associated with electromagnetic oscillations differ respectively from those of the corresponding electric vectors by

• 3)

Which one of the following is not an electromagnetic waves?

• 4)

Calcium or Barium salts in bunsen flame, CO2, N2 molecule, NH3 gas in a discharge tube gives_______.

• 5)

__________discovered electromagnetic induction.

#### 12th Standard Physics English Medium Electromagnetic Induction and Alternating Current Reduced Syllabus Important Questions With Answer Key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. Th e co-efficient of self-induction of the coil is

• 2)

A circular coil with a cross-sectional area of 4 cm2 has 10 turns. It is placed at the centre of a long solenoid that has 15 turns/cm and a cross-sectional area of 10 cm2. The axis of the coil coincides with the axis of the solenoid. What is their mutual inductance?

• 3)

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

• 4)

In a series resonant RLC circuit, the voltage across 100 Ω resistor is 40 V. The resonant frequency ω is 250 rad/s. If the value of C is 4 μF, then the voltage across L is

• 5)

In an oscillating LC circuit, the maximum charge on the capacitor is Q. The charge on the capacitor when the energy is stored equally between the electric and magnetic fields is

#### 12th Standard Physics English Medium Electromagnetic Induction and Alternating Current Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

An electron moves on a straight line path XY as shown in the figure. The coil abcd is adjacent to the path of the electron. What will be the direction of current, if any, induced in the coil?

• 2)

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. Th e co-efficient of self-induction of the coil is

• 3)

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

• 4)

An emf of 12V is induced when the current in the coil changes at the rate of 40 A S-1. The coefficient of self induction of the coil is

• 5)

Transformer works on

#### 12th Standard Physics English Medium Magnetism and Magnetic Effects of Electric Current Reduced Syllabus Important Questions with Answer key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

Th e force experienced by a particle having mass m and charge q accelerated through a potential diff erence V when it is kept under perpendicular magnetic field $\vec { B }$ is

• 2)

Th ree wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. Th ey are placed in a uniform magnetic fi eld and same electric current is passed through them. Which of the following loop confi guration will experience greater torque ?

• 3)

A wire of length l carries a current I along the Y direction and magnetic field is given by $\vec { B } =\frac { \beta }{ \sqrt { 3 } } =(\hat { i } +\hat { j } +\hat { k } )T.$ The magnitude of Lorentz force acting on the wire is

• 4)

Direction of magnetic force on a positive charge moving in a magnetic field is given by

• 5)

Consider the motion of a charged particle in a uniform magnetic field directed into the paper. If velocity v of the particle is in the plane of the paper, the charged particle will describe a

#### 12th Standard Physics English Medium Magnetism and Magnetic Effects of Electric Current Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

The magnetic fi eld at the center O of the following current loop is

• 2)

An electron moves straight inside a charged parallel plate capacitor of uniform charge density σ. Th e time taken by the electron to cross the parallel plate capacitor when the plates of the capacitor are kept under constant magnetic fi eld of induction $\vec { B }$is

• 3)

Th ree wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. Th ey are placed in a uniform magnetic fi eld and same electric current is passed through them. Which of the following loop confi guration will experience greater torque ?

• 4)

A wire of length l carries a current I along the Y direction and magnetic field is given by $\vec { B } =\frac { \beta }{ \sqrt { 3 } } =(\hat { i } +\hat { j } +\hat { k } )T.$ The magnitude of Lorentz force acting on the wire is

• 5)

The BH curve for a ferromagnetic material is shown in the figure. The material is placed inside a long solenoid which contains 1000 turns/cm. The current that should be passed in the solenonid to demagnetize the ferromagnet completely is

#### 12th Standard Physics English Medium Current Electricity Reduced Syllabus Important Questions with Answer key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

A wire connected to a power supply of 230 V has power dissipation P1. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case power dissipation is P2. The ratio $\frac{P_2}{P_1}$ is

• 2)

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, the resistance of a 60W bulb for use in USA will be

• 3)

When 'n' resistors of equal resistance (R) are connected in series and in parallel respectively,then the ratio of their effective resistance is

• 4)

A potential difference is applied an the ends of a metallic wire. If the potential difference is doubled, the drift velocity

• 5)

A bird sitting on an insulated wire carrying a current feels quite safe because

#### 12th Standard Physics English Medium Current Electricity Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

There is a current of 1.0 A in the circuit shown below. What is the resistance of P ?

• 2)

When 'n' resistors of equal resistance (R) are connected in series and in parallel respectively,then the ratio of their effective resistance is

• 3)

An unknown resistance is connected in parallel with a 15$\Omega$ resistance and a 12V battery. What is the value of the unknown resistance if the current in the circuit is 2A?

• 4)

Kirchoff's I law i.e, $\Sigma i=0$ at a junction, deals with the conservation of

• 5)

Resistance increases with increases in temperature for

#### 12th Standard Physics English Medium Electrostatics Reduced Syllabus Important Questions with Answer key 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

The total electric fl ux for the following closed surface which is kept inside water

• 3)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 4)

In electrostatics if the charges are in motion, another force named __________ comes into play in addition to coulomb force

• 5)

_______ and Coulomb's law form fundamental principles of electrostatics

#### 12th Standard Physics English Medium Electrostatics Reduced Syllabus Important Questions 2021 - by Sarojini - Tiruppur - Jan 27, 2021 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

The total electric fl ux for the following closed surface which is kept inside water

• 3)

_______ and Coulomb's law form fundamental principles of electrostatics

• 4)

A force of 40 N is acting between two charges in air if the space between then is filled with glass εr = 8. Then the force between then is

• 5)

The expression for electric field in vector form is

#### 12th Standard Physics English Medium Reduced Syllabus Model Question paper with answer key - 2021 Part - 2 - by Sarojini - Tiruppur - Jan 25, 2021 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

The total electric fl ux for the following closed surface which is kept inside water

• 3)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 4)

The figure shows tow parallel equipotential surface A and B kept at a small distance 'r' a part from each other. A point change of Q coulomb is taken from the surface A to B. The amount of net work done will be

• 5)

During charging a capacitor variation of potential V of the capacitor with time t as shown a

#### 12th Standard Physics English Medium Reduced Syllabus Model Question paper with answer key - 2021 Part - 1 - by Sarojini - Tiruppur - Jan 25, 2021 - View & Read

• 1)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 2)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 3)

Two identical coils, each with N turns and radius R are placed coaxially at a distance R as shown in the fi gure. If I is the current passing through the loops in the same direction, then the magnetic field at a point P which is at exactly at$\frac { R }{ 2 }$ distance between two coils is

• 4)

A thin semi-circular conducting ring (PQR) of radius r is falling with its plane vertical in a horizontal magnetic fi eld B, as shown in the fi gure.

The potential diff erence developed across the ring when its speed v, is

• 5)

An inductor 20 mH, a capacitor 50 μF and a resistor 40 Ω are connected in series across a source of emf v = 10 sin 340 t. The power loss in AC circuit is

#### 12th Standard Physics English Medium Reduced Syllabus Model Question paper - 2021 Part - 2 - by Sarojini - Tiruppur - Jan 25, 2021 - View & Read

• 1)

• 2)

Two short bar magnets have magnetic moments 1.20 Am2 and 1.00 Am2 respectively. They are kept on a horizontal table parallel to each other with their north poles pointing towards the south. They have a common magnetic equator and are separated by a distance of 20.0 cm. The value of the resultant horizontal magnetic induction at the mid-point O of the line joining their centers is (Horizontal components of Earth’s magnetic induction is 3.6 x 10-5 Wb m-2 )

• 3)

Th e electrical series circuit in digital form is

• 4)

A current gain for, a transistor working as CB amplifier is 0.90. If emitter current is 10 mA, then base current is

• 5)

Digital circuits can be made to be respective use of:

#### 12th Standard Physics English Medium Reduced Syllabus Model Question paper - 2021 Part - 1 - by Sarojini - Tiruppur - Jan 25, 2021 - View & Read

• 1)

An uncharged metal sphere is placed between two equal and oppositely charged metal plates. The nature of lines of force will be

• 2)

In three phase AC generator the three coils are fastened rigidly together and are displaced from each other by an angle

• 3)

In an a.c. circuit with an inductor

• 4)

In a LCR series a.c, circuit, the phase difference between current and voltage is 60°. If the net reactance of the circuit is 17.32Ω, the value of the resistance is

• 5)

Which of the following is used to study crystal structure?

#### 12th Standard Physics English Medium Reduced Syllabus Important Questions with Answer key - 2021 Part - 2 - by Sarojini - Tiruppur - Jan 25, 2021 - View & Read

• 1)

What physical quantities may X and Y represent? [Y represents the first mentioned quantity].

• 2)

Which one of the following pair of particles move with same velocity along the same circular path in a uniform magnetic field?

• 3)

This works on the principle of Tangent Law

• 4)

An α-particle enters a magnetic field of 1T with a velocity 106 m/s in a direction perpendicular to the field. The force on α-particle is

• 5)

Which of the following electromagnetic radiation is used for viewing objects through fog

#### 12th Standard Physics English Medium Reduced Syllabus Important Questions with Answer key - 2021 Part - 1 - by Sarojini - Tiruppur - Jan 25, 2021 - View & Read

• 1)

By using law of conservation of electric charge balance the following equations:
92U238 90Th234 ________.

• 2)

There is a current of 1.0 A in the circuit shown below. What is the resistance of P ?

• 3)

An unknown resistance is connected in parallel with a 15$\Omega$ resistance and a 12V battery. What is the value of the unknown resistance if the current in the circuit is 2A?

• 4)

The instantaneous values of alternating current and voltage in a circuit are $i=\frac { 1 }{ \sqrt { 2 } } sin\left( 100\pi t \right)$ A and v=$=\frac { 1 }{ \sqrt { 2 } } sin\left( 100\pi t+\frac { \pi }{ 3 } \right) V.$The average power in watts consumed in the circuit is

• 5)

Lenz's law is in accordance with the law of

#### 12th Standard Physics English Medium Reduced Syllabus Important Questions - 2021 Part - 2 - by Sarojini - Tiruppur - Jan 25, 2021 - View & Read

• 1)

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is

• 2)

The emf of a battery is 3 volts and internal resistance 0.125 $\Omega$ . The difference of potential
at the terminal of battery when connected across an external resistance of 1 $\Omega$ is

• 3)

Peltier effect is the converse of

• 4)

Kirchoff's II law isa consequence of conservation of________

• 5)

Which one of the following is correct. According to Biot-Savart law, the magnetic induction is directly proportional to

#### 12th Standard Physics English Medium Reduced Syllabus Important Questions - 2021 Part - 1 - by Sarojini - Tiruppur - Jan 25, 2021 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 3)

The total electric fl ux for the following closed surface which is kept inside water

• 4)

The electric field created by a _________ is basically a non-uniform electric field.

• 5)

The unit for electric susceptibility is

#### 12th Standard Physics Recent Developments in Physics English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

Which one of the following is the natural nanomaterial

• 2)

The method of making nanomaterial by assembling the atoms is called

• 3)

The materials used in Robotics are

• 4)

The technology used for stopping the brain from processing pain is

• 5)

The gravitational waves were theoretically proposed by

#### 12st Standard Physics Recent Developments in Physics English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

The particle size of ZnO material is 30 nm. Based on the dimension it is classified as

• 2)

The blue print for making ultra durable synthetic material is mimicked from

• 3)

The alloys used for muscle wires in Robots are

• 4)

The particle which gives mass to protons and neutrons are

• 5)

__________ Scanning Electron Micrograph (SEM) showing the nano structures on the surface of a leaf from a lotus plant

#### 12th Standard Physics Communication Systems English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

The signal is aff ected by noise in a communication system

• 2)

The internationally accepted frequency deviation for the purpose of FM broadcasts

• 3)

The loss of strengh of a signal while propagating through a medium is known as_________.

• 4)

Modulation is the process of superposing

• 5)

Large band width for higher data is achieved by using

#### 12th Standard Physics Communication Systems English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

The output transducer of the communication system converts the radio signal into ________.

• 2)

The variation of frequency of carrier wave with respect to the amplitude of the modulating signal is called _______.

• 3)

The frequency range of 3 MHz to 30 MHz is used for

• 4)

All medium wave signals received during day time use __________ wave propagation

• 5)

The radiowaves after refraction from different part of ionosphere on reaching the earth are called as

#### 12th Standard Physics Semiconductor Electronics English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

Doping a semiconductor results in

• 2)

When a transistor is fully switched on, it is said to be

• 3)

Th e electrical series circuit in digital form is

• 4)

By adding _________ impurity in intrinsic semi conductor, p type semiconductor is made. Charge of these p type semiconductoris ____________

• 5)

The behaviour of Ge as semi-conductor is due to width of:

#### 12th Standard Physics Semiconductor Electronics English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

The barrier potential of a silicon diode is approximately

• 2)

The primary use of a zener diode is

• 3)

The light emitted in an LED is due to

• 4)

The specific characteristic of a common emitter amplifier is

• 5)

If the input to the NOT gate is A = 1011, its output is

#### 12th Standard Physics Atomic and Nuclear physics English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

In a hydrogen atom, the electron revolving in the fourth orbit, has angular momentum equal to

• 2)

The electric potential between a proton and an electron is given by $V={ V }_{ 0 }in\left( \frac { r }{ { r }_{ 0 } } \right)$, where r0 is a constant. Assume that Bohr atom model is applicable of nth orbit rn with the principal quantum number n is

• 3)

The nucleus is approximately spherical in shape. Then the surface area of nucleus having mass number A varies as

• 4)

The half-life period of a radioactive element A is same as the mean life time of another radioactive element B. Initially both have the same number of atoms. Then

• 5)

The circumference of an electron's orbit of radius r must be an integral multiple of de Broglie wavelength that is

#### 12th Standard Physics Atomic and Nuclear physics English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

Suppose an alpha particle accelerated by a potential of V volt is allowed to collide with a nucleus whose atomic number is Z, then the distance of closest approach of alpha particle to the nucleus is

• 2)

The ratio of the wavelengths for the transition from n=2 to n=1 in Li++, He+ and H is

• 3)

the nuclear radius of 27 al is 3.6 fermi, the approximate nuclear radius of 64Cu is

• 4)

A radioactive nucleus (initial mass number A and atomic number Z) emits 2α and 2 positrons. The ratio of number of neutrons to that of proton in the final nucleus will be

• 5)

A system consists of N0 nucleus at t=0. The number of nuclei remaining after half of a half-life (that is, at time t=$\frac{q}{2}T_\frac{1}{2}$)

#### 12th Standard Physics Dual Nature of Radiation and Matter English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would

• 2)

Two radiations with photon energies 0.9 eV and 3.3 eV respectively are falling on a metallic surface successively. If the work function of the metal is 0.6 eV, then the ratio of maximum speeds of emitted electrons will be

• 3)

The mean wavelength of light from sun is taken to be 550 nm and its mean power is 3.8 × 1026W. The number of photons received by the human eye per second on the average from sunlight is of the order of

• 4)

The work functions for metals A, B and C are 1.92 eV, 2.0 eV and 5.0 eV respectively. The metals which will emit photoelectrons for a radiation of wavelength 4100$\\ \\ \mathring { A } \\$ is/are

• 5)

The work function of a metal is hvo' Light of frequency v falls on this metal. The photoelectric effect will take: place only if

#### 12th Standard Physics Dual Nature of Radiation and Matter English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

The wavelength λe of an electron and λp of a photon of same energy E are related by

• 2)

A light source of wavelength 520 nm emits 1.04 × 1015 photons per second while the second source of 460 nm produces 1.38 × 1015 photons per second. Then the ratio of power of second source to that of first source is

• 3)

Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is

• 4)

Emission of electrons by the absorption of heat energy is called_______emission.

• 5)

P and E denote the linear momentum and energy of a photon. If the wavelength is decreased

#### 12th Standard Physics Optics English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is,

• 2)

The radius of curvature of curved surface at a thin planoconvex lens is 10 cm and the refractive index is 1.5. If the plane surface is silvered, then the focal length will be,

• 3)

Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are

• 4)

First diffraction minimum due to a single slit of width 1.0×10–5 cm is at 30o. Then wavelength of light used is,

• 5)

One of the of Young’s double slits is covered with a glass plate as shown in figure. The position of central maximum will,

#### 12th Standard Physics Optics English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

The speed of light in an isotropic medium depends on,

• 2)

An object is placed in front of a convex mirror of focal length of f and the maximum and minimum distance of an object from the mirror such that the image formed is real and magnified.

• 3)

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index,

• 4)

An air bubble in glass slab of refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness of the slab is,

• 5)

A plane glass is placed over a various coloured letters (violet, green, yellow, red) The letter which appears to be raised more is,

#### 12th Standard Physics Electromagnetic Waves English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

If the amplitude of the magnetic fi eld is 3 × 10−6 T, then amplitude of the electric fi eld for a electromagnetic waves is

• 2)

Th e electric and the magnetic field, associated with an electromagnetic wave, propagating along X axis can be represented by

• 3)

A radiation of energy E falls normally on a perfectly refl ecting surface. Th e momentum transferred to the surface

• 4)

Which one of them is used to produce a propagating electromagnetic wave?.

• 5)

Which of the following is NOT true for electromagnetic waves?

#### 12th Standard Physics Electromagnetic Waves English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

The dimension of $\frac { 1 }{ { \mu }_{ 0 }{ \varepsilon }_{ 0 } }$ is

• 2)

Which of the following electromagnetic radiation is used for viewing objects through fog

• 3)

If the magnetic monopole exists, then which of the Maxwell’s equation to be modified?.

• 4)

Which of the following is an electromagnetic wave?

• 5)

Let E = Eo sin[106 x -ωt] be the electric field of plane electromagnetic wave, the value of ω is

#### 12th Standard Physics Electromagnetic Induction and Alternating Current English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. Th e co-efficient of self-induction of the coil is

• 2)

A circular coil with a cross-sectional area of 4 cm2 has 10 turns. It is placed at the centre of a long solenoid that has 15 turns/cm and a cross-sectional area of 10 cm2. The axis of the coil coincides with the axis of the solenoid. What is their mutual inductance?

• 3)

In a series RL circuit, the resistance and inductive reactance are the same. Then the phase difference between the voltage and current in the circuit is

• 4)

An inductor 20 mH, a capacitor 50 μF and a resistor 40 Ω are connected in series across a source of emf v = 10 sin 340 t. The power loss in AC circuit is

• 5)

Lenz's law is in accordance with the law of

#### 12th Standard Physics Electromagnetic Induction and Alternating Current English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

An electron moves on a straight line path XY as shown in the figure. The coil abcd is adjacent to the path of the electron. What will be the direction of current, if any, induced in the coil?

• 2)

Th e fl ux linked with a coil at any instant t is given by $\Phi$B =10t2−50t+ 250 . The induced emf at t = 3s is

• 3)

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

• 4)

The instantaneous values of alternating current and voltage in a circuit are $i=\frac { 1 }{ \sqrt { 2 } } sin\left( 100\pi t \right)$ A and v=$=\frac { 1 }{ \sqrt { 2 } } sin\left( 100\pi t+\frac { \pi }{ 3 } \right) V.$The average power in watts consumed in the circuit is

• 5)

Electromagnetic induction is-not used in

#### 12th Standard Physics Magnetism and magnetic effects of electric current English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

An electron moves straight inside a charged parallel plate capacitor of uniform charge density σ. Th e time taken by the electron to cross the parallel plate capacitor when the plates of the capacitor are kept under constant magnetic fi eld of induction $\vec { B }$is

• 2)

A wire of length l carries a current I along the Y direction and magnetic field is given by $\vec { B } =\frac { \beta }{ \sqrt { 3 } } =(\hat { i } +\hat { j } +\hat { k } )T.$ The magnitude of Lorentz force acting on the wire is

• 3)

A non-conducting charged ring of charge q, mass m and radius r is rotated with constant angular speed ω. Find the ratio of its magnetic moment with angular momentum is

• 4)

A flat dielectric disc of radius R carries an excess charge on its surface. The surface charge density is σ. The disc rotates about an axis perpendicular to its plane passing through the center with angular velocity ω. Find the magnitude of the torque on the disc if it is placed in a uniform magnetic field whose strength is B which is directed perpendicular to the axis of rotation

• 5)

In a thermocouple, the temperature of cold junction is 30°C and the neutral temperature is 310°C. The temperature of inversion is

#### 12th Standard Physics Magnetism and magnetic effects of electric current English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

The magnetic fi eld at the center O of the following current loop is

• 2)

Th e force experienced by a particle having mass m and charge q accelerated through a potential diff erence V when it is kept under perpendicular magnetic field $\vec { B }$ is

• 3)

A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively.
The magnetic induction at the center of the spiral is

• 4)

A bar magnet of length l and magnetic moment M is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be

• 5)

The BH curve for a ferromagnetic material is shown in the figure. The material is placed inside a long solenoid which contains 1000 turns/cm. The current that should be passed in the solenonid to demagnetize the ferromagnet completely is

#### 12th Standard Physics Current Electricity English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

A wire of resistance 2 ohms per meter is bent to form a circle of radius 1m. Th e equivalent resistance between its two diametrically opposite points, A and B as shown in the fi gure is

• 2)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 3)

There is a current of 1.0 A in the circuit shown below. What is the resistance of P ?

• 4)

The temperature coefficient of resistance of a wire is 0.00125 per °C. At 300 K, its resistance is 1 Ω. The resistance of the wire will be 2 Ω at

• 5)

The electrical resistivity of a thin copper wire and a thick copper wire are respectively ${ P }_{ 1 }\Omega$ m and ${ P }_{ 2 }\Omega$ m Then.

#### 12th Standard Physics Current Electricity English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

Th e following graph shows current versus voltage values of some unknown conductor. What is the resistance of this conductor?

• 2)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 3)

What is the value of resistance of the following resistor?

• 4)

A wire connected to a power supply of 230 V has power dissipation P1. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case power dissipation is P2. The ratio $\frac{P_2}{P_1}$ is

• 5)

In a large building, there are 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80W and 1 heater of 1kW are connected. The voltage of electric mains is 220V. The minimum capacity of the main fuse of the building will be

#### 12th Standard Physics Electrostatics English Medium Free Online Test One Mark questions with Answer Key 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

What is the ratio of the charges $\left| \frac { { q }_{ 1 } }{ { q }_{ 2 } } \right|$ for the following electric field line pattern?

• 2)

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric fl ux through each Gaussian surface in increasing order.

• 3)

The total electric fl ux for the following closed surface which is kept inside water

• 4)

Rank the electrostatic potential energies for the given system of charges in increasing order.

• 5)

Three capacitors are connected in triangle as shown in the figure. The equivalent capacitance between the points A and C is

#### 12th Standard Physics Electrostatics English Medium Free Online Test One Mark questions 2020 - 2021 - by Sarojini - Tiruppur - Oct 13, 2020 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

A thin conducting spherical shell of radius R has a charge Q which is uniformly distributed on its surface. The correct plot for electrostatic potential due to this spherical shell is

• 3)

Three capacitors are connected in triangle as shown in the figure. The equivalent capacitance between the points A and C is

• 4)

In a hydrogen atom the electron revolves around the proton in an orbit of 0.53 $\mathring { A }$. The potential produced by the electron on the nuleus is

• 5)

The electric field created by a _________ is basically a non-uniform electric field.

#### 12th Standard Physics English Medium Free Online Test one mark questions with answer key 2020 - Part Ten - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

If voltage applied on a capacitor is increased from V to 2V, choose the correct conclusion

• 2)

The electric field created by a _________ is basically a non-uniform electric field.

• 3)

Which of the following cannot be the units of electric field intensity?

• 4)

A wire of resistance 2 ohms per meter is bent to form a circle of radius 1m. Th e equivalent resistance between its two diametrically opposite points, A and B as shown in the fi gure is

• 5)

Temperature co-effieient of resistance for metals is

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Ten - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Two points A and B are maintained at a potential of 7 V and -4 V respectively. The work done in moving 50 electrons from A to B is

• 2)

The time taken by a conductor to reach electrostatic equilibrium is in the order of

• 3)

The force between like charges is _________.

• 4)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 5)

The equivalent resistance between A and Bin the figure is

#### 12th Standard Physics English Medium Free Online Test one mark questions with answer key 2020 - Part Nine - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 2)

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

• 3)

What physical quantities may X and Y represent? [Y represents the first mentioned quantity].

• 4)

The electric flux is ________ if the electric field lines enter the closed surface.

• 5)

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, the resistance of a 60W bulb for use in USA will be

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Nine - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 2)

In electrostatics if the charges are in motion, another force named __________ comes into play in addition to coulomb force

• 3)

Van de Graaff generator produces an electrostatic potential difference of_______ volts.

• 4)

When a point charge of 6mC is moved between two points in an electric field, the work done is 1.8 x 10-5 J. The potential difference between the two points is

• 5)

Near a charged object A another earthed object B is placed. Charges are induced on B. If B is removed. After that the charge on A ________.

#### 12th Standard Physics English Medium Free Online Test one mark questions with answer key 2020 - Part Eight - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

If voltage applied on a capacitor is increased from V to 2V, choose the correct conclusion

• 2)

Two charged bodies of charges +q, -3q are brought in contact and separated. The charges prossed by each body after separation.

• 3)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 4)

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is

• 5)

The temperature coefficient of resistance is positive__________.

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Eight - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Three capacitors are connected in triangle as shown in the figure. The equivalent capacitance between the points A and C is

• 2)

What will happen if two conducting spheres are separately charged and then brought in contact?

• 3)

During charging a capacitor variation of potential V of the capacitor with time t as shown a

• 4)

The total dipole moment per unit volume of the dielectric is________.

• 5)

The repulsive force between two like charges of 1 coulomb each separated by a distance of 1 m in vacuum is equal to :

#### 12th Standard Physics English Medium Free Online Test one mark questions with answer key 2020 - Part Seven - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 2)

A non-conducting material which has no free electrons is called

• 3)

The electric flux through a surface will be minimum when the angle between Eand A is

• 4)

Charge Q on a capacitor varies with voltage Vas shown in graph, where Q is along X-axis and V along Y-axis. The area of triangle OAB represents

• 5)

A Gaussian surface in the figure is shown by dotted line. The electric field on the surface will be

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Seven - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

• 2)

The value of constant 'K' in coulomb law is

• 3)

Four plates each of area 'N. and inferplate separation 'd' are placed as shown in figure. The two inner plates are connected to the point 'B' and outer to point 'A'. What is equivalent capacitance?

• 4)

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

• 5)

Which of the following has negative temperature coefficient of resistance?

#### 12th Standard Physics English Medium Free Online Test one mark questions with answer key 2020 - Part Six - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

A thin conducting spherical shell of radius R has a charge Q which is uniformly distributed on its surface. The correct plot for electrostatic potential due to this spherical shell is

• 2)

Charge Q on a capacitor varies with voltage Vas shown in graph, where Q is along X-axis and V along Y-axis. The area of triangle OAB represents

• 3)

When an electric dipole is placed in a uniform external electric field parallel to the field, it will experience_________.

• 4)

A wire of resistance 2 ohms per meter is bent to form a circle of radius 1m. Th e equivalent resistance between its two diametrically opposite points, A and B as shown in the fi gure is

• 5)

Four resistances are connected to a 5V battery of negligible internal resistance as shown what is the potential across $2\Omega$?

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Six - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 2)

Based on Franklin's convention amber rods are_________.

• 3)

The direction of electric field at a point the equatorial line due to an electric dipole is

• 4)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 5)

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

#### 12th Standard Physics English Medium Free Online Test one mark questions with answer key 2020 - Part Five - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 2)

An isolated metal sphere of radius 'r' is given a charge' q'. The potential energy of the sphere is

• 3)

The expression for electric potentid difference is

• 4)

Torque experienced by a dipole in an electric field when it is placed parallel to the field is ______.

• 5)

What is the current out of the battery?

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Five - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Rank the electrostatic potential energies for the given system of charges in increasing order.

• 2)

A positively charged body 'A' has been brought near a brass cylinder 'B' mounted on a glass stand as shown in the figure. The potential of 'B' will be

• 3)

What physical quantities may X and Y represent? [Y represents the first mentioned quantity].

• 4)

Electrostatics deals with the _________

• 5)

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, the resistance of a 60W bulb for use in USA will be

#### 12th Standard Physics English Medium Free Online Test One Mark Questions with Answer Key 2020 - Part Four - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

A thin conducting spherical shell of radius R has a charge Q which is uniformly distributed on its surface. The correct plot for electrostatic potential due to this spherical shell is

• 2)

The given figure is a plot of lines of force due to two charges q1 & q2 find out the sign of charges

• 3)

A wire connected to a power supply of 230 V has power dissipation P1. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case power dissipation is P2. The ratio $\frac{P_2}{P_1}$ is

• 4)

In the case of Wheatstone)s Bridge) the bridge balance condition will be obtained only when____

• 5)

Two short bar magnets have magnetic moments 1.20 Am2 and 1.00 Am2 respectively. They are kept on a horizontal table parallel to each other with their north poles pointing towards the south. They have a common magnetic equator and are separated by a distance of 20.0 cm. The value of the resultant horizontal magnetic induction at the mid-point O of the line joining their centers is (Horizontal components of Earth’s magnetic induction is 3.6 x 10-5 Wb m-2 )

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Four - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

If voltage applied on a capacitor is increased from V to 2V, choose the correct conclusion

• 2)

A force of 40 N is acting between two charges in air if the space between then is filled with glass εr = 8. Then the force between then is

• 3)

Two copper spheres A and B of same size are charged to same potential. A is hollow and B is solid. Which of the two holds more charge?

• 4)

Which graph shows the variation of electric field E due to a hollow spherical conductor of radius R as a function of distance from the centre of the sphere?

• 5)

A closed system contains four charges -8.1C, 14.6C, 20.2C and -200 mC. The total charge in the system_______.

#### 12th Standard Physics English Medium Free Online Test one mark questions with answer key 2020 - Part Three - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 2)

Charge per unit volume is called

• 3)

The negative gradient of potential is

• 4)

A charge QμC is placed at the center of a cube. The flux coming out from any surface will be

• 5)

Surface density of charge on a sphere of radius R in terms of electric intensity E at a distance r in free space is

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Three - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric fl ux through each Gaussian surface in increasing order.

• 2)

In a parallel plate capacitor of capacitance C, a metal sheet is inserted between the plates, parallel to them. The thickness of the sheet is half of the separation between the plates. The capacitance now becomes

• 3)

In a hollow spherical shell potential (V) changes with respect to distance (r) from centre.
$\left[ { V }_{ inside }=\frac { Q }{ 4\pi { \varepsilon }_{ 0 }R } r\le R,\quad { V }_{ outside }=\frac { Q }{ 4\pi { \varepsilon }_{ 0 }r } r\ge R,V\alpha \frac { 1 }{ r } \right]$

• 4)

Two wires of A and B with circular cross section made up of the same material with equal lengths. Suppose RA = 3 RB, then what is the ratio of radius of wire A to that of B?

• 5)

When the free electrons are moving in all possible directions, the value of the current produced is_______

#### 12th Standard Physics English Medium Free Online Test Book Back 1 Mark Questions with Answer Key - Part Three - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Two points A and B are maintained at a potential of 7 V and -4 V respectively. The work done in moving 50 electrons from A to B is

• 2)

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, the resistance of a 60W bulb for use in USA will be

• 3)

A non-conducting charged ring of charge q, mass m and radius r is rotated with constant angular speed ω. Find the ratio of its magnetic moment with angular momentum is

• 4)

Th e current i fl owing in a coil varies with time as shown in the fi gure. Th e variation of induced emf with time would be

• 5)

Consider an oscillator which has a charged particle and oscillates about its mean position with a frequency of 300 MHz. Th e wavelength of electromagnetic waves produced by this oscillator is

#### 12th Standard Physics English Medium Free Online Test Book Back One Mark Questions - Part Three - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

The total electric fl ux for the following closed surface which is kept inside water

• 2)

Th e following graph shows current versus voltage values of some unknown conductor. What is the resistance of this conductor?

• 3)

A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively.
The magnetic induction at the center of the spiral is

• 4)

Th e fl ux linked with a coil at any instant t is given by $\Phi$B =10t2−50t+ 250 . The induced emf at t = 3s is

• 5)

Consider an oscillator which has a charged particle and oscillates about its mean position with a frequency of 300 MHz. Th e wavelength of electromagnetic waves produced by this oscillator is

#### 12th Standard Physics English Medium Free Online Test Book Back 1 Mark questions with Answer Key - Part Two - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

• 2)

Two short bar magnets have magnetic moments 1.20 Am2 and 1.00 Am2 respectively. They are kept on a horizontal table parallel to each other with their north poles pointing towards the south. They have a common magnetic equator and are separated by a distance of 20.0 cm. The value of the resultant horizontal magnetic induction at the mid-point O of the line joining their centers is (Horizontal components of Earth’s magnetic induction is 3.6 x 10-5 Wb m-2 )

• 3)

An inductor 20 mH, a capacitor 50 μF and a resistor 40 Ω are connected in series across a source of emf v = 10 sin 340 t. The power loss in AC circuit is

• 4)

Which of the following is an electromagnetic wave?

• 5)

A ray of light strikes a glass plate at an angle 60o. If the reflected and refracted rays are perpendicular to each other, the refractive index of the glass is,

#### 12th Standard Physics English Medium Free Online Test Book Back one Mark questions - Part Two - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Three capacitors are connected in triangle as shown in the figure. The equivalent capacitance between the points A and C is

• 2)

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

• 3)

A flat dielectric disc of radius R carries an excess charge on its surface. The surface charge density is σ. The disc rotates about an axis perpendicular to its plane passing through the center with angular velocity ω. Find the magnitude of the torque on the disc if it is placed in a uniform magnetic field whose strength is B which is directed perpendicular to the axis of rotation

• 4)

In an oscillating LC circuit, the maximum charge on the capacitor is Q. The charge on the capacitor when the energy is stored equally between the electric and magnetic fields is

• 5)

Which of the following is NOT true for electromagnetic waves?

#### 12th Standard Physics English Medium Free Online Test Creative One Mark questions with Answer Key - Part Five - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

What physical quantities may X and Y represent? [Y represents the first mentioned quantity].

• 2)

In RLC series AC circuit at resonance:

• 3)

Which of the following forms a virtual and erect image for all position of the object.

• 4)

Sodium and copper have work functions of 2.3eV and 4.5eV respectively, then the ratio of the wavelengths is nearest to

• 5)

The de Broglie wavelength of electron accelerated with a potential V is ________

#### 12th Standard Physics English Medium Free Online Test Creative 1 Mark questions - Part Five - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

The unit for electric susceptibility is

• 2)

In an electrical arrangement as shown the equivalent resistance between X and Y will be

• 3)

Parts of the energy is used in an electric motor and the remaining part of the energy is dissipated in form of

• 4)

The magnitude of the induced emf in a conductor depends on the

• 5)

Speed of electromagnetic waves through vacuum is equal to

#### 12th Standard Physics English Medium Free Online Test Creative One Mark questions with Answer Key - Part Four - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

The magnitude of torque on dipole is maximum if

• 2)

The expression for water equivalent is

• 3)

For an ideal transformer __________

• 4)

Accelerated charges would produce

• 5)

_________ spectra are used for making dyes

#### 12th Standard Physics English Medium Free Online Test Creative 1 Mark questions - Part Four - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

In a hydrogen atom the electron revolves around the proton in an orbit of 0.53 $\mathring { A }$. The potential produced by the electron on the nuleus is

• 2)

If the specific resistance of a potentiometer wire is 10-7 Om and current flowing through it . is 0.1 amp, cross - sectional area of wire is 10-6 m2, then potential gradient will be

• 3)

The reciprocal of conductivity is________

• 4)

Direction of magnetic force on a positive charge moving in a magnetic field is given by

• 5)

Electric filament lamp gives rise to

#### 12th Standard Physics English Medium Free Online Test Creative One Mark questions with Answer Key - Part Three - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Electric field intensity and electric potential are related by_________.

• 2)

When a current of 5 A flows through a conductor of resistance 3 $\Omega$ the loss of power due to joule heating effect is_________

• 3)

Which one of the following represents corrent magnetic field lines?

• 4)

If a secondary coil has 40 turns, and a primary coil with 20 turns is charged with 50V of potential difference, then potential difference in secondary would be

• 5)

Electromagnetic waves are discovered by

#### 12th Standard Physics English Medium Free Online Test Creative 1 Mark questions - Part Three - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Eight mercury droplets having a radius of 1 mm and charge of 0.066 pC each merge to form one droplet. Its potential is

• 2)

The potential due to a single point charge falls as

• 3)

The emf of a battery is 3 volts and internal resistance 0.125 $\Omega$ . The difference of potential
at the terminal of battery when connected across an external resistance of 1 $\Omega$ is

• 4)

If a current I is flowing in a straight wire parallel to X-axis and magnetic field is in y-axis then the wire experiences

• 5)

The Q factor of an a.c. circuit containing a resistance R, inductance L and capacitor C is

#### 12th Standard Physics English Medium Free Online Test Creative One Mark questions with Answer Key - Part Two - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

The concept of 'Field' was introduced by

• 2)

A condenser is charged to a potential of 200V and has a charge of 0.1C. The energy stored in it is

• 3)

If the specific resistance of a potentiometer wire is 10-7 Om and current flowing through it . is 0.1 amp, cross - sectional area of wire is 10-6 m2, then potential gradient will be

• 4)

Which of the following is an identical.

• 5)

The resistance of the wire varies inversely as

#### 12th Standard Physics English Medium Free Online Test Creative 1 Mark questions - Part Two - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

An uncharged metal sphere is placed between two equal and oppositely charged metal plates. The nature of lines of force will be

• 2)

An unknown resistance is connected in parallel with a 15$\Omega$ resistance and a 12V battery. What is the value of the unknown resistance if the current in the circuit is 2A?

• 3)

Consider the motion of a charged particle in a uniform magnetic field directed into the paper. If velocity v of the particle is in the plane of the paper, the charged particle will describe a

• 4)

In the following figure the key is dosed. Which statement is correct?

• 5)

If the velocity of light in a medium is 2.25 x 108 ms-1 then the refractive index of the medium will be

#### 12th Standard Physics English Medium Free Online Test Volume 2 One Mark questions 2020 - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index,

• 2)

When light is incident on a soap film of thickness 5×10–5 cm, the wavelength of light reflected maximum in the visible region is 5320 Å. Refractive index of the film will be,

• 3)

Two plane mirrors are at 45° to each other. If an object is placed between them than the number of images will be

• 4)

A ray of light is incidenting normally on a .plane mirror. The angle of reflection will be

• 5)

A point object 0 is placed between two plane mirrors as shown is figure The distance by mirror M2 from it are

#### 12th Standard Physics English Medium Free Online Test Volume 1 One Mark questions with Answer Key 2020 - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

The total electric fl ux for the following closed surface which is kept inside water

• 2)

A thin conducting spherical shell of radius R has a charge Q which is uniformly distributed on its surface. The correct plot for electrostatic potential due to this spherical shell is

• 3)

The relative permittivity of water is _______.

• 4)

What will happen if two conducting spheres are separately charged and then brought in contact?

• 5)

A non-conducting material which has no free electrons is called

#### 12th Standard Physics English Medium Free Online Test Volume 2 One Mark questions with Answer Key 2020 - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

A ray of light travelling in a transparent medium of refractive index n falls, on a surface separating the medium from air at an angle of incidents of 45o. The ray can undergo total internal reflection for the following n,

• 2)

One of the of Young’s double slits is covered with a glass plate as shown in figure. The position of central maximum will,

• 3)

A plane mirror produces a magnification of

• 4)

A plane mirror is placed at the bottom of the tank containing a liquid of refractive index J.1.P is a small object at a height h above the mirror, an observer O-vertically above P outside the liquid. See p and its image in the mirror. The apparent distance between these two will be

• 5)

The focal length of a convex mirror is 20 cm, its radius of the curvature will be

#### 12th Standard Physics English Medium Free Online Test Volume 1 One Mark questions 2020 - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

The total electric fl ux for the following closed surface which is kept inside water

• 2)

The relative permittivity of water is _______.

• 3)

An isolated metal sphere of radius 'r' is given a charge' q'. The potential energy of the sphere is

• 4)

The direction of electric field at a point the equatorial line due to an electric dipole is

• 5)

When three capacitors are joined in series, the total capacitance is

#### 12th Standard Physics English Medium Free Online Test Creative One Mark questions with Answer Key - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

The figure shows tow parallel equipotential surface A and B kept at a small distance 'r' a part from each other. A point change of Q coulomb is taken from the surface A to B. The amount of net work done will be

• 2)

Eight mercury droplets having a radius of 1 mm and charge of 0.066 pC each merge to form one droplet. Its potential is

• 3)

What will happen if two conducting spheres are separately charged and then brought in contact?

• 4)

Temperature co-effieient of resistance for metals is

• 5)

In an electrical arrangement as shown the equivalent resistance between X and Y will be

#### 12th Standard Physics English Medium Free Online Test Creative 1 Mark questions - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

The relative permittivity of water is _______.

• 2)

The expression for electric field in vector form is

• 3)

A condenser of 2μF capacitance is charged steadily from 0 to 5 coulomb. Which of the following graphs correctly represents the variation of potential difference across its plates with respect to the charge on the condensor [Q = C V ]

• 4)

Which of the following has negative temperature coefficient of resistance?

• 5)

In an electrical arrangement as shown the equivalent resistance between X and Y will be

#### 12th Standard Physics English Medium Free Online Test Book Back 1 mark questions with Answer Key - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric fl ux through each Gaussian surface in increasing order.

• 2)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 3)

Three capacitors are connected in triangle as shown in the figure. The equivalent capacitance between the points A and C is

• 4)

A wire of resistance 2 ohms per meter is bent to form a circle of radius 1m. Th e equivalent resistance between its two diametrically opposite points, A and B as shown in the fi gure is

• 5)

In a large building, there are 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80W and 1 heater of 1kW are connected. The voltage of electric mains is 220V. The minimum capacity of the main fuse of the building will be

#### 12th Standard Physics English Medium Free Online Test Book Back one Mark questions - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

If voltage applied on a capacitor is increased from V to 2V, choose the correct conclusion

• 2)

Two metallic spheres of radii 1 cm and 3 cm are given charges of -1 x 10-2 C and 5 x 10-2 C respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is

• 3)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 4)

Two wires of A and B with circular cross section made up of the same material with equal lengths. Suppose RA = 3 RB, then what is the ratio of radius of wire A to that of B?

• 5)

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is

#### 12th Standard Physics English Medium Free Online Test one mark questions with answer key 2020 - Part Two - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 2)

What will happen if two conducting spheres are separately charged and then brought in contact?

• 3)

Which of the following statement on equipotential surface is wrong?

• 4)

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

• 5)

A bar magnet of length l and magnetic moment M is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Two - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

What will happen if two conducting spheres are separately charged and then brought in contact?

• 3)

In a parallel plate capacitor of capacitance C, a metal sheet is inserted between the plates, parallel to them. The thickness of the sheet is half of the separation between the plates. The capacitance now becomes

• 4)

A charge q1 exerts force on charge q2. If another charge q3 is brought near, the force of q1, exerted on q2, will be

• 5)

By using law of conservation of electric charge balance the following equations:
92U238 90Th234 ________.

#### 12th Standard Physics English Medium Free Online Test one mark questions with answer key 2020 - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 2)

The figure shows tow parallel equipotential surface A and B kept at a small distance 'r' a part from each other. A point change of Q coulomb is taken from the surface A to B. The amount of net work done will be

• 3)

Which one of the following relation is correct?

• 4)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 5)

A metallic block has no potential difference applied across it, then the mean velocity of free electrons is

#### 12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - by Sarojini - Tiruppur - Oct 12, 2020 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

Three capacitors are connected in triangle as shown in the figure. The equivalent capacitance between the points A and C is

• 3)

The given figure is a plot of lines of force due to two charges q1 & q2 find out the sign of charges

• 4)

A condenser of 2μF capacitance is charged steadily from 0 to 5 coulomb. Which of the following graphs correctly represents the variation of potential difference across its plates with respect to the charge on the condensor [Q = C V ]

• 5)

Near a charged object A another earthed object B is placed. Charges are induced on B. If B is removed. After that the charge on A ________.

#### 12th Standard Physics English Medium Model 5 Mark Creative Questions (New Syllabus 2020) - by Sarojini - Tiruppur - Sep 29, 2020 - View & Read

• 1)

It requires 50 μJ of work to carry a 2C charge from point R to S. What is the potential difference between these points?

• 2)

An infinite number of charges each equal to q are placed along X-axis at x = 1, x = 2, x = 3, x = 4, x = 8 and soon. Find the electric field at the point x = 0 due to this set up of charges.

• 3)

Explain the variation of resistivity of conductor and semiconductor with change in temperature

• 4)

Using the concept of drift velocity of charge carries in a conductor, deduce the relationship between circuit density and resistivity of the conductor?

• 5)

An aluminium wire of diameter 0.24 cm is connected in series to a copper wire of diameter 0.16 cm. The wires carry an electric current of 10 A. Determine the current density in aluminium wire.

#### 12th Standard Physics English Medium Model 5 Mark Book Back Questions (New Syllabus 2020) - by Sarojini - Tiruppur - Sep 29, 2020 - View & Read

• 1)

Calculate the electric flux through the rectangle of sides 5 cm and 10 cm kept in the region of a uniform electric field 100 NC-1. The angle θ is 600. Suppose θ becomes zero, what is the electric flux?

• 2)

Find the equivalent capacitance between P and Q for the configuration shown below in the figure (a).

• 3)

Consider an electron travelling with a speed vo and entering into a uniform electric field
$\vec { E }$ which is perpendicular to $\vec { { v }_{ 0 } }$ as shown in the Figure. Ignoring gravity, obtain the electron’s acceleration, velocity and position as functions of time.

• 4)

A point charge of +10 μC is placed at a distance of 20 cm from another identical point charge of +10 μC. A point charge of -2 μC is moved from point a to b as shown in the figure. Calculate the change in potential energy of the system? Interpret your result.

• 5)

From the given circuit,

Find
i) Equivalent emf of the combination
ii) Equivalent internal resistance
iii) Total current
iv) Potential difference across external resistance
v) Potential difference across each cell

#### 12th Standard Physics English Medium Sample 5 Mark Creative Questions (New Syllabus 2020) - by Sarojini - Tiruppur - Sep 29, 2020 - View & Read

• 1)

Explain in detail the Electrostatic Potential difference between the charges.

• 2)

How many electrons are there in one coulomb of negative charge?

• 3)

In the circuit shown in figure. Find
(i) The equivalent capacitance and
(ii) The charge stored in each capcicitor

• 4)

Explain the variation of resistivity of conductor and semiconductor with change in temperature

• 5)

Two metallic wires PI &P2 of the same material & same length but different cross sectional areas Al & A2 are joined together & connected to a source of emf. Find the ratio of the drift velocities of free electrons in the two wires when they are connected (i) in series & (ii) in parallel.

#### 12th Physics English Medium Sample 5 Mark Book Back Questions (New Syllabus 2020) - by Sarojini - Tiruppur - Sep 29, 2020 - View & Read

• 1)

Four charges are arranged at the corners of the square PQRS of side a as shown in the figure.(a) Find the work required to assemble these charges in the given configuration. (b) Suppose a charge q′ is brought to the center of the square, by keeping the four charges fixed at the corners, how much extra work is required for this?

• 2)

A parallel plate capacitor has square plates of side 5 cm and separated by a distance of 1 mm.
(a) Calculate the capacitance of this capacitor.
(b) If a 10 V battery is connected to the capacitor, what is the charge stored in any one of the plates? (The value of εo = 8.85 x 10-12 Nm2 C-2)

• 3)

Draw the free body diagram for the following charges as shown in the figure (a), (b) and (c).

• 4)

Calculate the resultant capacitances for each of the following combinations of capacitors.

• 5)

Two electric bulbs marked 20 W – 220 V and 100 W – 220 V are connected in series to 440 V supply. Which bulb will be fused?

#### 12th Physics English Medium Important 5 Mark Creative Questions (New Syllabus 2020) - by Sarojini - Tiruppur - Sep 29, 2020 - View & Read

• 1)

It requires 50 μJ of work to carry a 2C charge from point R to S. What is the potential difference between these points?

• 2)

What charge would be required to electrify a sphere of radius 25cm. So as to get a surface charge density of $\frac{3}{\pi}$ cm-1?

• 3)

A parallel plate capacitor has plate area, 25 cm+2 and a separation of 2 mm between the plates. The capacitor is connected to a battery of 12V. Find the charge on the capacitor.

• 4)

Two insulated charged copper sphere A and B have their centres separated by a distance of 50cm.
(i) What is the force of electrostatic repulsion, if the charge on each is 6.5 X 10-7C and the radii of A and B are negligible compared to the distance of separation?
(ii) What is the force of repulsion, if each sphere is charged double the above amount and the distance between them is halved?

• 5)

Write mathematical relation between mobility & drift velocity of charge carriers in a conductor (ii) mobility & relaxation time (or) mean free time.

#### Important 5 Mark Book Back Questions (New Syllabus 2020) - by Sarojini - Tiruppur - Sep 29, 2020 - View & Read

• 1)

A water molecule has an electric dipole moment of 6.3 × 10-30 Cm. A sample contains 1022 water molecules, with all the dipole moments aligned parallel to the external electric field of magnitude 3 × 105 NC-1. How much work is required to rotate all the water molecules from θ = 00 to 900?

• 2)

A parallel plate capacitor filled with mica having εr = 5 is connected to a 10 V battery. The area of the parallel plate is 6 m2 and separation distance is 6 mm.
(a) Find the capacitance and stored charge.
(b) After the capacitor is fully charged, the battery is disconnected and the dielectric is removed carefully.
Calculate the new values of capacitance, stored energy and charge.

• 3)

For the given capacitor configuration
(a) Find the charges on each capacitor
(b) potential difference across them
(c) energy stored in each capacitor

• 4)

A battery has an emf of 12 V and connected to a resistor of 3 Ω. The current in the circuit is 3.93 A. Calculate (a) terminal voltage and the internal resistance of the battery (b) power delivered by the battery and power delivered to the resistor

• 5)

In a Wheatstone’s bridge P = 100 Ω, Q = 1000 Ω and R = 40 Ω. If the galvanometer shows zero deflection, determine the value of S.

#### 12th Standard Physics English Medium Model 3 Mark Creative Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Sep 01, 2020 - View & Read

• 1)

What happens when and electric dipole is held in a non-uniform electric field?

• 2)

What is dielectrics or insulators.

• 3)

How does one can understand the temperature dependence of resistivity of a conductor?

• 4)

Find the expression for the equivalent emf & internal resistance of the series combination of cells

• 5)

Mention the properties of Magnetic field lines?

#### 12th Standard Physics English Medium Model 3 Mark Book Back Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Sep 01, 2020 - View & Read

• 1)

Calculate the electrostatic force and gravitational force between the proton and the electron in a hydrogen atom. They are separated by a distance of 5.3 × 10-11 m. The magnitude of charges on the electron and proton are 1.6 × 10-19 C. Mass of the electron is me = 9.1 × 10-31 kg and mass of proton is mp = 1.6 × 10-27 kg.

• 2)

Calculate the electric field due to a dipole on its axial line and equatorial plane.

• 3)

Obtain the expression for energy stored in the parallel plate capacitor.

• 4)

A potential difference across 24 Ω resistor is 12 V. What is the current through the resistor?

• 5)

Five resistors are connected in the configuration as shown in the figure. Calculate the equivalent resistance between the points a and b.

#### 12th Standard Physics English Medium Sample 3 Mark Creative Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Sep 01, 2020 - View & Read

• 1)

What is principle used in Microwave oven? Explain.

• 2)

Explain the Lightning arrester or lightning conductor.

• 3)

How does one can understand the temperature dependence of resistivity of a conductor?

• 4)

Explain Peltier effect.

• 5)

State that a current carrying loop behaves as a magnetic dipole. Hence write an expression for its magnetic dipole moment.

#### 12th Standard Physics English Medium Sample 3 Mark Book Back Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Sep 01, 2020 - View & Read

• 1)

Calculate the number of electrons in one coulomb of negative charge.

• 2)

Calculate the electric field at points P, Q for the following two cases, as shown in the figure.
(a) A positive point charge +1 μC is placed at the origin.
(b) A negative point charge -2 μC is placed at the origin.

• 3)

Explain in detail Coulomb’s law and its various aspects.

• 4)

Discuss the various properties of conductors in electrostatic equilibrium.

• 5)

A potential difference across 24 Ω resistor is 12 V. What is the current through the resistor?

#### 12th Standard Physics English Medium Important 3 Mark Creative Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Sep 01, 2020 - View & Read

• 1)

Derive the expressions for the potential energy of a system of point charges.

• 2)

Explain the Lightning arrester or lightning conductor.

• 3)

Derive a relation between internal resisance and emf of a cell

• 4)

Tabulate the difference between Coulomb's law and Biot-Savort's law.

• 5)

In a certain region of space, electric field $\vec { E }$ and magnetic field $\vec { B }$ are perpendicular to each other. An electron enters in the region perpendicular to the direction of both $\vec { B }$ & $\vec { E }$ and moves undeflected. Find the velocity of electron.

#### 12th Standard Physics English Medium Important 3 Mark Book Back Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Sep 01, 2020 - View & Read

• 1)

Calculate the number of electrons in one coulomb of negative charge.

• 2)

A block of mass m and positive charge q is placed on an insulated frictionless inclined plane as shown in the figure. A uniform electric field E is applied parallel to the inclined surface such that the block is at rest. Calculate the magnitude of the electric field E.

• 3)

Calculate the electric dipole moment for the following charge configurations.

• 4)

Derive an expression for the torque experienced by a dipole due to a uniform electric field.

• 5)

Obtain the expression for energy stored in the parallel plate capacitor.

#### 12th Standard Physics English Medium Model 2 Mark Creative Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 29, 2020 - View & Read

• 1)

What is a Capacitor?

• 2)

Represent the variation of electric field due to point charge Q with
a) magnitude of charge Q
b) r and
c) $\frac{1}{r^2}$ where r is the distance of the observation point from the charge. graphically.

• 3)

How does the energy stored. in a capacitor change it
(i) after disconnecting the battery, the plates of a charged capacitor are moved faster.
(ii) The battery remaining connected capacitance c∝$\frac{1}{d}$, when plates of capacitor.

• 4)

Define instantaneous current

• 5)

The resistivity of materials depends upon what parameters?

#### 12th Standard Physics English Medium Model 2 Mark Book Back Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 29, 2020 - View & Read

• 1)

What is mean by ‘Electric field lines’?

• 2)

What is Polarisation?

• 3)

Define electrical resistivity

• 4)

What is Seebeck effect?

• 5)

State Coulomb’s inverse law.

#### 12th Standard Physics English Medium Sample 2 Mark Creative Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 29, 2020 - View & Read

• 1)

What are induced dipoles.

• 2)

An electric dipole is held in a uniform electric field.
(i) Straight the net force acting on it is zero.
(ii) The dipole is alignment parallel to the field. find the work done in rotating it through the angle of 180o.

• 3)

Two isolated metal spheres A &B have radii R & 2R respectively and same charge q. Find which of the two spheres have greater energy density just outside the surface of the sphere.

• 4)

Aparallel plate capacitor is charged by a battery after some time, the battery is disconnected and a dielectric slab with its thickness equal to the plate so reparation is insected between the plates. How will
(i) the capacitance of the capacitor
(ii) potential difference between the plates &
(iii) the energy stored in the capacitor the affected?
Qo - charge; Vo - potential difference,
Co - capacitance, Eo- electric field.
U0 - energy spred, before the dielectric slab is inserted.
${ Q }_{ 0 }={ C }_{ 0 }{ V }_{ 0 };\frac { { B }_{ 0 } }{ d } ;{ U }_{ 0 }=\frac { 1 }{ 2 } { C }_{ 0 }{ v }_{ 0 }^{ 2 }$

• 5)

Gauss law is true for any closed surface, no matter what its shape or size is. Justify.

#### 12th Standard Physics English Medium Sample 2 Mark Book Back Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 29, 2020 - View & Read

• 1)

Write a short note on superposition principle.

• 2)

Define ‘electric flux’.

• 3)

State macroscopic form of Ohm’s law.

• 4)

What do you mean by internal resistance of a cell?

• 5)

Define magnetic dipole moment.

#### 12th Standard Physics English Medium Important 2 Mark Creative Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 29, 2020 - View & Read

• 1)

What are induced dipoles.

• 2)

Asphere of charge +Q is fixed. Asmaller sphere of charge +q is placed near the larger sphere and released from rest. The small sphere will move away from large sphere with
a. decreasing velocity & decreasing acceleration.
b. decreasing velocity & increasing acceleration.
c. decreasing velocity &constant acceleration d. increasing velocity & decreasing acceleration
e. increasing velocity & increasing acceleration
Which of the above statement is correct? Explain.

• 3)

Aparallel plate capacitor is charged by a battery after some time, the battery is disconnected and a dielectric slab with its thickness equal to the plate so reparation is insected between the plates. How will
(i) the capacitance of the capacitor
(ii) potential difference between the plates &
(iii) the energy stored in the capacitor the affected?
Qo - charge; Vo - potential difference,
Co - capacitance, Eo- electric field.
U0 - energy spred, before the dielectric slab is inserted.
${ Q }_{ 0 }={ C }_{ 0 }{ V }_{ 0 };\frac { { B }_{ 0 } }{ d } ;{ U }_{ 0 }=\frac { 1 }{ 2 } { C }_{ 0 }{ v }_{ 0 }^{ 2 }$

• 4)

How does the energy stored. in a capacitor change it
(i) after disconnecting the battery, the plates of a charged capacitor are moved faster.
(ii) The battery remaining connected capacitance c∝$\frac{1}{d}$, when plates of capacitor.

• 5)

Define mean free time $\tau$

#### 12th Standard Physics English Medium Important 2 Mark Book Back Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 29, 2020 - View & Read

• 1)

Write a short note on superposition principle.

• 2)

Define ‘electrostatic potential energy’.

• 3)

Distinguish between drift velocity and mobility.

• 4)

What is electric power and electric energy?

• 5)

What is Peltier effect?

#### 12th Standard Physics English Medium Model 1 Mark Creative Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 25, 2020 - View & Read

• 1)

The figure shows tow parallel equipotential surface A and B kept at a small distance 'r' a part from each other. A point change of Q coulomb is taken from the surface A to B. The amount of net work done will be

• 2)

Two condensers (capacitors) of capacity C1 and C2 are connected in parallel. A charge Q given to then is shared. The ratio of the charges Q is

• 3)

The expression for the electric field due to a surface of total charge 'Q' is given by

• 4)

The unit for electric flux is

• 5)

The temperature co-efficient of resistance for alloys is

#### 12th Standard Physics English Medium Model 1 Mark Book Back Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 25, 2020 - View & Read

• 1)

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

• 2)

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is

• 3)

Th ree wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. Th ey are placed in a uniform magnetic fi eld and same electric current is passed through them. Which of the following loop confi guration will experience greater torque ?

• 4)

A simple pendulum with charged bob is oscillating with time period T and let θ be the angular displacement. If the uniform magnetic field i switched ON in a direction perpendicular to the plane of oscillation then

• 5)

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

#### 12th Standard Physics English Medium Sample 1 Mark Creative Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 25, 2020 - View & Read

• 1)

The relative permittivity of water is _______.

• 2)

The force experienced by a unit charge is called

• 3)

Two charges are kept at a distance in air what should be the relative permittivity of the medium in which the two charges should be kept at the same distance so that they experience half of the force which they experienced in air?

• 4)

For continuous charge distributions, _____ methods can be used.

• 5)

Two charged bodies of charges +q, -3q are brought in contact and separated. The charges prossed by each body after separation.

#### 12th Standard Physics English Medium Sample 1 Mark Book Back Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 25, 2020 - View & Read

• 1)

Two points A and B are maintained at a potential of 7 V and -4 V respectively. The work done in moving 50 electrons from A to B is

• 2)

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

• 3)

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is

• 4)

A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively.
The magnetic induction at the center of the spiral is

• 5)

A non-conducting charged ring of charge q, mass m and radius r is rotated with constant angular speed ω. Find the ratio of its magnetic moment with angular momentum is

#### 12th Standard Physics English Medium Important 1 Mark Creative Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 25, 2020 - View & Read

• 1)

The relative permittivity of water is _______.

• 2)

The electric potential V as a function of distance x (metres) is given by V = ( 5x2 + 10x -9) volt. The value of electric field at a point x = 1m is

• 3)

The unit for electric susceptibility is

• 4)

The capacitance of a parallel plate capacitor increases from 5μf of 50μf when a dielectric is filled between the plates. The permitivity of the dielectric is

• 5)

If the specific resistance of a potentiometer wire is 10-7 Om and current flowing through it . is 0.1 amp, cross - sectional area of wire is 10-6 m2, then potential gradient will be

#### 12th Standard Physics English Medium Important 1 Mark Book Back Questions (New Syllabus) 2020 - by Sarojini - Tiruppur - Aug 25, 2020 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 3)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 4)

What is the value of resistance of the following resistor?

• 5)

In a large building, there are 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80W and 1 heater of 1kW are connected. The voltage of electric mains is 220V. The minimum capacity of the main fuse of the building will be

#### 12th standard Physics full portion important One Mark Questions - 2020 - by Sarojini - Tiruppur - Mar 20, 2020 - View & Read

• 1)

The total electric fl ux for the following closed surface which is kept inside water

• 2)

If voltage applied on a capacitor is increased from V to 2V, choose the correct conclusion

• 3)

At Infinity (i.e r = ∞), the electrostatic potential (V) is

• 4)

Electrostatics deals with the _________

• 5)

Th e following graph shows current versus voltage values of some unknown conductor. What is the resistance of this conductor?

#### 12th Physics - Recent Developments in Physics - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

Distinguish between Nanoscience and Nanotechnology.

• 2)

What is the difference between Nano materials and Bulk materials?

• 3)

Give any two examples for "Nano" in nature.

• 4)

• 5)

Why steel is preferred in making Robots?

#### 12th Physics Communication Systems - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

Give the factors that are responsible for transmission impairments.

• 2)

Distinguish between wireline and wireless communication? Specify the range of electromagnetic waves in which it is used.

• 3)

Explain centre frequency or resting frequency in frequency modulation.

• 4)

• 5)

What do you mean by Internet of Things?

#### 12th Physics Semiconductor Electronics - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

Distinguish between Intrinsic and extrinsic semiconductors.

• 2)

What do you mean by doping?

• 3)

A diode is called as a unidirectional device. Explain.

• 4)

What do you mean by leakage current in a diode?

• 5)

Discuss the biasing polarities in an NPN and PNP transistors

#### 12th Physics Atomic and Nuclear physics - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

What are cathode rays?

• 2)

Write down the postulates of Bohr atom model.

• 3)

What is distance of dosest approach?

• 4)

Define atomic mass unit u.

• 5)

What is binding energy of a nucleus? Give it expression.

#### 12th Physics Dual Nature of Radiation and Matter - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

Define work function of a metal. Give its unit.

• 2)

How does photocurrent vary with the intensity of the incident light?

• 3)

What is a photo cell? Mention the different types of photocells.

• 4)

State de Broglie hypothesis.

• 5)

A proton and an electron have same kinetic energy. Which one has greater de Broglie wavelength. Justify.

#### 12th Physics Optics - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

Explain the working of an endoscope.

• 2)

Arrive at lens equation from lens maker's formula.

• 3)

Write a short note on quantum theory of light.

• 4)

Define wavefront

• 5)

How does wavefront division provide coherent sources?

#### 12th Physics Electromagnetic Waves - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

What is displacement current?

• 2)

What are electromagnetic waves?

• 3)

Write down the integral form of modified Ampere’s circuital law.

• 4)

Explain the concept of intensity of electromagnetic waves.

• 5)

What is meant by Fraunhofer lines?

#### 12th Physics Electromagnetic Induction and Alternating Current - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

What is meant by electromagnetic induction?

• 2)

State Faraday’s laws of electromagnetic induction.

• 3)

Mention the ways of producing induced emf.

• 4)

What do you mean by self-induction?

• 5)

List out the advantages of stationary armature-rotating field system of AC generator.

#### 12th Physics Magnetism and Magnetic Effects of Electric Current - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

What is meant by magnetic induction?

• 2)

Define magnetic flux.

• 3)

State Coulomb’s inverse law.

• 4)

State Biot-Savart’s law.

• 5)

Compare dia, para and ferro-magnetism.

#### 12th Physics Current Electricity - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

Distinguish between drift velocity and mobility.

• 2)

State microscopic form of Ohm’s law.

• 3)

What is electric power and electric energy?

• 4)

Write down the various forms of expression for power in electrical circuit.

• 5)

What do you mean by internal resistance of a cell?

#### 12th Physics Electrostatics - Two Marks Study Materials - by 8682895000 - Jan 22, 2020 - View & Read

• 1)

Write down Coulomb’s law in vector form and mention what each term represents.

• 2)

What are the differences between Coulomb force and gravitational force?

• 3)

What is mean by ‘Electric field lines’?

• 4)

Define ‘electrostatic potential”.

• 5)

What is dielectric strength?

#### 12th Physics - Full Portion Five Marks Questions - by 8682895000 - Jan 20, 2020 - View & Read

• 1)

The following figure represents the electric potential as a function of x – coordinate. Plot the corresponding electric field as a function of x.

• 2)

A parallel plate capacitor filled with mica having εr = 5 is connected to a 10 V battery. The area of the parallel plate is 6 m2 and separation distance is 6 mm.
(a) Find the capacitance and stored charge.
(b) After the capacitor is fully charged, the battery is disconnected and the dielectric is removed carefully.
Calculate the new values of capacitance, stored energy and charge.

• 3)

The following figure shows a complex network of conductors which can be divided into two closed loops like ACE and ABC. Apply Kirchoff’s voltage rule.

• 4)

In a Wheatstone’s bridge P = 100 Ω, Q = 1000 Ω and R = 40 Ω. If the galvanometer shows zero deflection, determine the value of S.

• 5)

The current through an element is shown in the figure. Determine the total charge that pass through the element at a) t = 0 s, b) t = 2 s, c) t = 5s

#### 12th Physics - Full Portion Three Marks Question - by 8682895000 - Jan 20, 2020 - View & Read

• 1)

Consider two point charges q1 and q2 at rest as shown in the figure.

They are separated by a distance of 1m. Calculate the force experienced by the two charges for the following cases:
(a) q1 = +2μC and q2 = +3μC
(b) q1 = +2μC and q2 = -3μC
(c) q1= +2μC and q2 = -3μC kept in water (εr = 80)

• 2)

Consider four equal charges q1,q2, q3 and q4 = q = +1μC located at four different points on a circle of radius 1m, as shown in the figure. Calculate the total force acting on the charge q1 due to all the other charges.

• 3)

(a) Calculate the electric potential at points P and Q as shown in the figure below.
(b) Suppose the charge +9μC is replaced by -9μC find the electrostatic potentials at points P and Q.

(c) Calculate the work done to bring a test charge +2μC from infinity to the point P. Assume the charge +9μC is held fixed at origin and +2μC is brought from infinity to P.

• 4)

Define potential difference and derive.

• 5)

Consider a rectangular block of metal of height A, width B and length C as shown in the figure.

If a potential difference of V is applied between the two faces A and B of the block (figure (a)), the current IAB is observed. Find the current that flows if the same potential difference V is applied between the two faces B and C of the block (figure (b)). Give your answers in terms of IAB.

#### 12th Physics - Full Portion Two Marks Study Materials - by 8682895000 - Jan 20, 2020 - View & Read

• 1)

What is an equipotential surface?

• 2)

Define ‘capacitance’. Give its unit.

• 3)

State microscopic form of Ohm’s law.

• 4)

Define temperature coefficient of resistance.

• 5)

What do you mean by internal resistance of a cell?

#### 12th Physics - Public Exam Model Question Paper 2019 - 2020 - by Sarojini - Tiruppur - Jan 17, 2020 - View & Read

• 1)

The force between like charges is _________.

• 2)

In a large building, there are 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80W and 1 heater of 1kW are connected. The voltage of electric mains is 220V. The minimum capacity of the main fuse of the building will be

• 3)

Th ree wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. Th ey are placed in a uniform magnetic fi eld and same electric current is passed through them. Which of the following loop confi guration will experience greater torque ?

• 4)

Above the neutral temperature the thermo emf

• 5)

In a transformer, eddy current loss is minimized by using

#### 12th Physics - Recent Developments in Physics Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

The alloys used for muscle wires in Robots are

• 2)

The particle which gives mass to protons and neutrons are

• 3)

__________ Scanning Electron Micrograph (SEM) showing the nano structures on the surface of a leaf from a lotus plant

• 4)

Best example for applications. of nano technology

• 5)

Zno is an example of __________

#### 12th Physics - Communication Systems Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

The output transducer of the communication system converts the radio signal into ________.

• 2)

The signal is aff ected by noise in a communication system

• 3)

The variation of frequency of carrier wave with respect to the amplitude of the modulating signal is called _______.

• 4)

The internationally accepted frequency deviation for the purpose of FM broadcasts

• 5)

The frequency range of 3 MHz to 30 MHz is used for

#### 12th Physics - Semiconductor Electronics Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

The primary use of a zener diode is

• 2)

Th e principle in which a solar cell operates

• 3)

Th e electrical series circuit in digital form is

• 4)

Which statement is incorrect regarding for p-n junction.

• 5)

The intrinsic semi-conductor has:

#### 12th Physics - Atomic and Nuclear Physics Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

The charge of cathode rays is

• 2)

The ratio of the wavelengths for the transition from n=2 to n=1 in Li++, He+ and H is

• 3)

Mp denotes the mass of the proton and Mn denotes mass of a neutron. A given nucleus of binding energy B, contains Z protons and N neutrons. The mass M(N,Z) of the nucleus is given by(where c is the speed of light)

• 4)

The ionization energy of hydrogen atom is -13.6e V. The energy corresponding to a transition between 3rd and 4th orbit is

• 5)

The total energy of electrons in the ground state of hydrogen atom is -13.6 eV. The k.E of an electron in the first excited state is

#### 12th Physics - Dual Nature of Radiation and Matter Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would

• 2)

The threshold wavelength for a metal surface whose photoelectric work function is 3.313 eV is

• 3)

The work function of a metal is hvo' Light of frequency v falls on this metal. The photoelectric effect will take: place only if

• 4)

Photoelectron effect supports quantum nature of light because

• 5)

A charged oil drop is suspended in uniform field of 3 x I04 Vm-1 so that it neither falls nor rises. The charge on the drop will be

#### 12th Physics - Optics Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index,

• 2)

The radius of curvature of curved surface at a thin planoconvex lens is 10 cm and the refractive index is 1.5. If the plane surface is silvered, then the focal length will be,

• 3)

First diffraction minimum due to a single slit of width 1.0×10–5 cm is at 30o. Then wavelength of light used is,

• 4)

Two plane mirrors are at 45° to each other. If an object is placed between them than the number of images will be

• 5)

A ray of light is incidenting normally on a .plane mirror. The angle of reflection will be

#### 12th Physics - Electromagnetic Waves Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

In an electromagnetic wave in free space the rms value of the electric fi eld is 3 V m−1. The peak value of the magnetic field is

• 2)

During the propagation of electromagnetic waves in a medium

• 3)

Let E = Eo sin[106 x -ωt] be the electric field of plane electromagnetic wave, the value of ω is

• 4)

Which of the following electromagnetic waves has the highest frequency?

• 5)

Which of the following E.M waves has the longest wavelength?

#### 12th Physics - Electromagnetic Induction and Alternating Current Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

Th e fl ux linked with a coil at any instant t is given by $\Phi$B =10t2−50t+ 250 . The induced emf at t = 3s is

• 2)

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. Th e co-efficient of self-induction of the coil is

• 3)

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

• 4)

A step-down transformer reduces the supply voltage from 220 V to 11 V and increase the current from 6 A to 100 A. Then its efficiency is

• 5)

In a series resonant RLC circuit, the voltage across 100 Ω resistor is 40 V. The resonant frequency ω is 250 rad/s. If the value of C is 4 μF, then the voltage across L is

#### 12th Physics - Magnetism and Magnetic Effects of Electric Current Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

Th e force experienced by a particle having mass m and charge q accelerated through a potential diff erence V when it is kept under perpendicular magnetic field $\vec { B }$ is

• 2)

A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively.
The magnetic induction at the center of the spiral is

• 3)

The vertical component of Earth’s magnetic field at a place is equal to the horizontal component. What is the value of angle of dip at this place?

• 4)

Which one of the following represents corrent magnetic field lines?

• 5)

An electron of mass 0.90 x 10-30kg under the action of a magnetic field moves in a circle of 2cm radius at a speed of 3 x 106 m/s if a proton of mass 1.8 x 10-27 kg was to move in a circle of the same radius in the same magnetic field, then its speed will be

#### 12th Physics - Current Electricity Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 2)

Two wires of A and B with circular cross section made up of the same material with equal lengths. Suppose RA = 3 RB, then what is the ratio of radius of wire A to that of B?

• 3)

In a large building, there are 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80W and 1 heater of 1kW are connected. The voltage of electric mains is 220V. The minimum capacity of the main fuse of the building will be

• 4)

Which of the following has negative temperature coefficient of resistance?

• 5)

The temperature co-efficient of resistance for alloys is

#### 12th Physics - Electrostatics Model Question Paper 1 - by 8682895000 - Jan 06, 2020 - View & Read

• 1)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 2)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 3)

Two points A and B are maintained at a potential of 7 V and -4 V respectively. The work done in moving 50 electrons from A to B is

• 4)

The value of constant 'K' in coulomb law is

• 5)

The electrostatic force is always greater in magnitude than gravitational force for_________ object.

#### 12th Physics - Recent Developments in Physics Model Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

The particle size of ZnO material is 30 nm. Based on the dimension it is classified as

• 2)

The alloys used for muscle wires in Robots are

• 3)

The technology used for stopping the brain from processing pain is

• 4)

George Devol invented the first digitally operated programmable robot called

• 5)

In __________ it was established that atoms are made up of electrons, protons and neutrons

#### 12th Physics - Communication Systems Model Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

The process of increasing the strength of a signal using an electric circuit is called

• 2)

Modulation is the process of superposing

• 3)

The device which is a combination of a receiver and a transmitter is

• 4)

The maximum carrier swing allowed in frequency modulation is :

• 5)

The resting frequency of FM transmitter is 98.5MHz. The allowed minimum and maximum frequency on either side of .the centre frequency are respectively.

#### 12th Physics - Semiconductor Electronics Model Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

Doping a semiconductor results in

• 2)

A forward biased diode is treated as

• 3)

C, Si and Ge have same no. of valence electrons. C is an insulator because energy required to take one electron out from

• 4)

By adding _________ impurity in intrinsic semi conductor, p type semiconductor is made. Charge of these p type semiconductoris ____________

• 5)

Assertion: Base current (IB) decreases and in turn increases the collector current.
Reason: Input signal (VS) decreases. the forward voltage across the emitterbase.
(a) Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) Assertion and Reason are true but Reason is the false explanation of the Assertion.
(c) Assertion is true but Reason is false.
(d) Assertion is false but Reason is true.

#### 12th Physics - Atomic and Nuclear Physics Practice Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

Suppose an alpha particle accelerated by a potential of V volt is allowed to collide with a nucleus whose atomic number is Z, then the distance of closest approach of alpha particle to the nucleus is

• 2)

The charge of cathode rays is

• 3)

In J.J Thomson e/m experiment, a beam of electron is replaced by that of muons (particle with same charge as that of electrons but mass 208 times that of electrons). No deflection condition is achieved only if

• 4)

The ratio of the wavelengths for the transition from n=2 to n=1 in Li++, He+ and H is

• 5)

The ground state energy of hydrogen atom is 13.6 eV. The energy needed to ionize H2 atom from its second excited state.

#### 12th Physics - Dual Nature of Radiation and Matter Practice Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

The wavelength λe of an electron and λp of a photon of same energy E are related by

• 2)

In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would

• 3)

P and E denote the linear momentum and energy of a photon. If the wavelength is decreased

• 4)

The work function of a metal is hvo' Light of frequency v falls on this metal. The photoelectric effect will take: place only if

• 5)

The minimum amount of energy required to liberate a photo electron from the metal surface is called as ________

#### 12th Physics - Optics Sample Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

The speed of light in an isotropic medium depends on,

• 2)

A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is,

• 3)

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index,

• 4)

The radius of curvature of curved surface at a thin planoconvex lens is 10 cm and the refractive index is 1.5. If the plane surface is silvered, then the focal length will be,

• 5)

To get three images of a single object, one should have two plane mirror at an angle of

#### 12th Physics - Electromagnetic Waves Model Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

The dimension of $\frac { 1 }{ { \mu }_{ 0 }{ \varepsilon }_{ 0 } }$ is

• 2)

If the amplitude of the magnetic fi eld is 3 × 10−6 T, then amplitude of the electric fi eld for a electromagnetic waves is

• 3)

Which of the following electromagnetic radiation is used for viewing objects through fog

• 4)

Assertion: Electromagnetic waves carries not only energy and momentum but also angular momentum.
Reason : Electromagnetic waves cannot be polarized.
(a) Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) Assertion and Reason are true but Reason is the false explanation of the Assertion.
(c) Assertion is true but Reason is false.
(d) Assertion is false but Reason is true.

• 5)

Assertion: Microwaves does not obey reflection and plarization.
Reason: Gamma rays are used in radio therapy for cancer treatment.
(a) Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) Assertion and Reason are true but Reason is the false explanation of the Assertion.
(c) Assertion is true but Reason is false.
(d) Assertion is false but Reason is true.

#### 12th Physics Electromagnetic Induction and Alternating Current Model Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

An electron moves on a straight line path XY as shown in the figure. The coil abcd is adjacent to the path of the electron. What will be the direction of current, if any, induced in the coil?

• 2)

Th e fl ux linked with a coil at any instant t is given by $\Phi$B =10t2−50t+ 250 . The induced emf at t = 3s is

• 3)

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. Th e co-efficient of self-induction of the coil is

• 4)

Th e current i fl owing in a coil varies with time as shown in the fi gure. Th e variation of induced emf with time would be

• 5)

$\frac{20}{\pi^2}H$inductor is connected to a capacitor of capacitance C. The value of C in order to impart maximum power at 50 Hz is

#### 12th Physics - Magnetism and Magnetic Effects of Electric Current Model Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

The magnetic fi eld at the center O of the following current loop is

• 2)

Th e force experienced by a particle having mass m and charge q accelerated through a potential diff erence V when it is kept under perpendicular magnetic field $\vec { B }$ is

• 3)

A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively.
The magnetic induction at the center of the spiral is

• 4)

What is meant by magnetic induction?

• 5)

Define magnetic flux.

#### 12th Physics - Current Electricity Model Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

Th e following graph shows current versus voltage values of some unknown conductor. What is the resistance of this conductor?

• 2)

A wire connected to a power supply of 230 V has power dissipation P1. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case power dissipation is P2. The ratio $\frac{P_2}{P_1}$ is

• 3)

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, the resistance of a 60W bulb for use in USA will be

• 4)

The temperature coefficient of resistance of a wire is 0.00125 per °C. At 300 K, its resistance is 1 Ω. The resistance of the wire will be 2 Ω at

• 5)

The emf of a battery is 3 volts and internal resistance 0.125 $\Omega$ . The difference of potential
at the terminal of battery when connected across an external resistance of 1 $\Omega$ is

#### 12th Standard Physics - Electrostatics Model Question Paper - by Sarojini - Tiruppur - Jan 02, 2020 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 3)

The electrostatic force is always greater in magnitude than gravitational force for_________ object.

• 4)

The relative permittivity of water is _______.

• 5)

An uncharged metal sphere is placed between two equal and oppositely charged metal plates. The nature of lines of force will be

#### 12th Physics - Electrostatics Model Question Paper - by Sarojini - Tiruppur - Dec 30, 2019 - View & Read

• 1)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 2)

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric fl ux through each Gaussian surface in increasing order.

• 3)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 4)

Rank the electrostatic potential energies for the given system of charges in increasing order.

• 5)

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

#### 12th Physics - Recent Developments in Physics Model Question Paper - by Sarojini - Tiruppur - Dec 03, 2019 - View & Read

• 1)

The alloys used for muscle wires in Robots are

• 2)

The gravitational waves were theoretically proposed by

• 3)

__________ Scanning Electron Micrograph (SEM) showing the nano structures on the surface of a leaf from a lotus plant

• 4)

_______ is synthesized top down approach

• 5)

Give any two examples for "Nano" in nature.

#### 12th Physics - Communication Systems Model Question Paper - by Sarojini - Tiruppur - Dec 03, 2019 - View & Read

• 1)

The signal is aff ected by noise in a communication system

• 2)

The frequency range of 3 MHz to 30 MHz is used for

• 3)

In a video signal for transmission of picture what value of bandwidth is used in communication system?

• 4)

Which of the following is an example of breadcast made of communication?

• 5)

The radio waves of frequency 30 MHz to 300 MHz belong to

#### 12th Physics - Semiconductor Electronics Model Question Paper - by Sarojini - Tiruppur - Dec 03, 2019 - View & Read

• 1)

The primary use of a zener diode is

• 2)

Th e principle in which a solar cell operates

• 3)

The specific characteristic of a common emitter amplifier is

• 4)

By adding _________ impurity in intrinsic semi conductor, p type semiconductor is made. Charge of these p type semiconductoris ____________

• 5)

The intrinsic semi-conductor has:

#### 12th Physics - Atomic and Nuclear Physics Model Question Paper - by Sarojini - Tiruppur - Dec 03, 2019 - View & Read

• 1)

The electric potential between a proton and an electron is given by $V={ V }_{ 0 }in\left( \frac { r }{ { r }_{ 0 } } \right)$, where r0 is a constant. Assume that Bohr atom model is applicable of nth orbit rn with the principal quantum number n is

• 2)

A radioactive nucleus (initial mass number A and atomic number Z) emits 2α and 2 positrons. The ratio of number of neutrons to that of proton in the final nucleus will be

• 3)

The half-life period of a radioactive element A is same as the mean life time of another radioactive element B. Initially both have the same number of atoms. Then

• 4)

The ionization energy of hydrogen atom is -13.6e V. The energy corresponding to a transition between 3rd and 4th orbit is

• 5)

The total energy of electrons in the ground state of hydrogen atom is -13.6 eV. The k.E of an electron in the first excited state is

#### 12th Physics - Dual Nature of Radiation and Matter Model Question Paper - by Sarojini - Tiruppur - Dec 03, 2019 - View & Read

• 1)

In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would

• 2)

In photoelectric emission, a radiation whose frequency is 4 times threshold frequency of a certain metal is incident on the metal. Th en the maximum possible velocity of the emitted electron will be

• 3)

The threshold wavelength for a metal surface whose photoelectric work function is 3.313 eV is

• 4)

The work functions for metals A, B and C are 1.92 eV, 2.0 eV and 5.0 eV respectively. The metals which will emit photoelectrons for a radiation of wavelength 4100$\\ \\ \mathring { A } \\$ is/are

• 5)

Light of wavelength falls on a metal having work function $\frac { { h }_{ c } }{ { \lambda }_{ 0 } }$. Photoelectric effect will place only if

#### 12th Physics - Optics Model Question Paper - by Sarojini - Tiruppur - Dec 03, 2019 - View & Read

• 1)

If the velocity and wavelength of light in air is Va and λa and that in water is Vw and λw, then the refractive index of water is,

• 2)

Stars twinkle due to,

• 3)

A ray of light travelling in a transparent medium of refractive index n falls, on a surface separating the medium from air at an angle of incidents of 45o. The ray can undergo total internal reflection for the following n,

• 4)

A man of length h requires a mirror of length at least equal to, to see his own complete image

• 5)

A man runs towards a mirror at a speed 15m/s. The speed of the image relative to the man is

#### 12th Physics - Electromagnetic Waves Model Question Paper - by Sarojini - Tiruppur - Nov 27, 2019 - View & Read

• 1)

Th e electric and the magnetic field, associated with an electromagnetic wave, propagating along X axis can be represented by

• 2)

During the propagation of electromagnetic waves in a medium

• 3)

Which one of them is used to produce a propagating electromagnetic wave?.

• 4)

Which of the following E.M waves has the longest wavelength?

• 5)

If the velocity of light in a medium is 2.25 x 108 ms-1 then the refractive index of the medium will be

#### 12th Physics - Electromagnetic Induction and Alternating Current Model Question Paper - by Sarojini - Tiruppur - Nov 27, 2019 - View & Read

• 1)

Th e fl ux linked with a coil at any instant t is given by $\Phi$B =10t2−50t+ 250 . The induced emf at t = 3s is

• 2)

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. Th e co-efficient of self-induction of the coil is

• 3)

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

• 4)

The self-inductance of a straight conductor is

• 5)

If a secondary coil has 40 turns, and a primary coil with 20 turns is charged with 50V of potential difference, then potential difference in secondary would be

#### 12th Physics - Magnetism and Magnetic Effects of Electric Current Model Question Paper - by Sarojini - Tiruppur - Nov 27, 2019 - View & Read

• 1)

Th e force experienced by a particle having mass m and charge q accelerated through a potential diff erence V when it is kept under perpendicular magnetic field $\vec { B }$ is

• 2)

A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively.
The magnetic induction at the center of the spiral is

• 3)

A wire of length l carries a current I along the Y direction and magnetic field is given by $\vec { B } =\frac { \beta }{ \sqrt { 3 } } =(\hat { i } +\hat { j } +\hat { k } )T.$ The magnitude of Lorentz force acting on the wire is

• 4)

Direction of magnetic force on a positive charge moving in a magnetic field is given by

• 5)

If a current I is flowing in a straight wire parallel to X-axis and magnetic field is in y-axis then the wire experiences

#### 12th Physics - Current Electricity Important Questions - by Sarojini - Tiruppur - Nov 21, 2019 - View & Read

• 1)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 2)

In a large building, there are 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80W and 1 heater of 1kW are connected. The voltage of electric mains is 220V. The minimum capacity of the main fuse of the building will be

• 3)

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is

• 4)

Which of the following has negative temperature coefficient of resistance?

• 5)

The temperature co-efficient of resistance for alloys is

#### 12th Physics - Electrostatics Important Questions - by Sarojini - Tiruppur - Nov 21, 2019 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

The total electric fl ux for the following closed surface which is kept inside water

• 3)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 4)

The electrostatic force is always greater in magnitude than gravitational force for_________ object.

• 5)

The relative permittivity of water is _______.

#### 12th Physics Half Yearly Model Question Paper 2019 - by Sarojini - Tiruppur - Nov 12, 2019 - View & Read

• 1)

Two points A and B are maintained at a potential of 7 V and -4 V respectively. The work done in moving 50 electrons from A to B is

• 2)

Three capacitors are connected in triangle as shown in the figure. The equivalent capacitance between the points A and C is

• 3)

A resistance of a metal wire of length AB is 2$\Omega$. Another wire of length PQ of the same metal with twice the diameter of the wire AB is found to have the same resistance of2$\Omega$. What is the length of PQ?

• 4)

The reciprocal of the resistance is__________

• 5)

A circular coil of radius 5 cm and 50 turns carries a current of 3 ampere. The magnetic dipole moment of the coil is

#### 12th Physics - Electromagnetic waves One Mark Questions with Answer - by Sarojini - Tiruppur - Nov 05, 2019 - View & Read

• 1)

Which of the following electromagnetic radiation is used for viewing objects through fog

• 2)

Let E = Eo sin[106 x -ωt] be the electric field of plane electromagnetic wave, the value of ω is

• 3)

The electric and magnetic fields of an electromagnetic wave are

• 4)

The wavelength range of ultra violet radiation is

• 5)

The phase and orientation of the magnetic vector associated with electromagnetic oscillations differ respectively from those of the corresponding electric vectors by

#### 12th Physics - Electromagnetic Induction and Alternating Current One Mark Questions with Answer - by Sarojini - Tiruppur - Nov 05, 2019 - View & Read

• 1)

An electron moves on a straight line path XY as shown in the figure. The coil abcd is adjacent to the path of the electron. What will be the direction of current, if any, induced in the coil?

• 2)

Electromagnetic induction is-not used in

• 3)

Lenz's law is in accordance with the law of

• 4)

Which of the following cannot be stepped up in a transformer?

• 5)

If a secondary coil has 40 turns, and a primary coil with 20 turns is charged with 50V of potential difference, then potential difference in secondary would be

#### 12th Physics - Magnetism and Magnetic Effects of Electric Current One Mark Questions with Answer - by Sarojini - Tiruppur - Nov 05, 2019 - View & Read

• 1)

The most suitable metal for permanent magnet is

• 2)

Direction of magnetic force on a positive charge moving in a magnetic field is given by

• 3)

Lorentz force generally refers to force experienced by a charge due to combined action of

• 4)

Two thin long parallel wires separated by a distancea' are carrying current I amp each. The magnitude of the force per unit length excited by one wire on the other is

• 5)

At a given place the horizontal component of earth's field is 0.2 x 10-4 Tesla. If a vertical wire carries a current of 30A upward, what is the magnitude and direction of the force on 1m of wire?

#### 12th Physics - Current Electricity One Mark Questions with Answer - by Sarojini - Tiruppur - Nov 05, 2019 - View & Read

• 1)

In a large building, there are 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80W and 1 heater of 1kW are connected. The voltage of electric mains is 220V. The minimum capacity of the main fuse of the building will be

• 2)

There is a current of 1.0 A in the circuit shown below. What is the resistance of P ?

• 3)

The colour code on a carbon resistor is red - red - black. The resistance of the resistor is?

• 4)

A square aluminum rod is 1 m long and 5 mm on edge. What must be the radius of another aluminum rod whose length is 1 m and which has the same resistance as that of square Aluminum rod?

• 5)

Five 3 resistances are arranged in a polygon (5 sides). What is the resistance between any two corners?

#### 12th Physics - Electrostatics One Marks Question with Answer - by Sarojini - Tiruppur - Nov 05, 2019 - View & Read

• 1)

An isolated metal sphere of radius 'r' is given a charge' q'. The potential energy of the sphere is

• 2)

Charge per unit volume is called

• 3)

The expression for the electric field due to a surface of total charge 'Q' is given by

• 4)

The electric flux is negative, if the angle between $\overset { \rightarrow }{ dA }$ and $\overset { \rightarrow }{ E }$ is

• 5)

In the given cricuit the effective capacitance between A and B will be

#### 12th Physics - Semiconductor Electronics Five Marks Questions - by Sarojini - Tiruppur - Nov 04, 2019 - View & Read

• 1)

The given circuit has two ideal diodes connected as shown in figure below. Calculate the current flowing through the resistance R1

• 2)

Four silicon diodes and a 10 Ω resistor are connected as shown in figure below. Each diode has a resistance of 1Ω. Find the current flows through the 18Ω resistor.

• 3)

Assuming VCEsat= 0.2 V and β = 50, find the minimum base current (IB) required to drive the transistor given in the figure to saturation.

• 4)

A transistor having a = 0.99 and VBE = 0.7V collector current, is given in the circuit. Find the value of the collector current.

• 5)

In the circuit shown in the figure, the BJT has a current gain (β) of 50. For an emitter - base voltage VEB = 600 mV, calculate the emitter - collector voltage VEC (in volts)

#### 12th Physics - Atomic and Nuclear Physics Five Marks Questions - by Sarojini - Tiruppur - Nov 04, 2019 - View & Read

• 1)

Assuming that energy released by the fission of a single $_{ 92 }^{ 235 }{ U }$ nucleus is 200MeV, calculate the number of fissions per second required to produce 1 watt power.

• 2)

Keezhadi (கீழடி), a small hamlet, has become one of the very important archeological places of Tamilandu. It is located in Sivagangai district. A lot of artefacts (gold coins, pottery, beads, iron tools, jewellery and charcoal, etc.) have been unearthed in Keezhadi which have given substantial evidence that an ancient urban civilization had thrived on the banks of river Vaigai. To determine the age of those materials, the charcoal of 200 g sent for carbon dating is given in the following figure(b). The activity of $_{ 6 }^{ 14 }{ C }$ is found to be 38 decays/s. Calculate the age of charcoal.

Figure (a) Keezhadi – excavation site

Figure (b) – Characol which was sent for carbon dating

• 3)

Calculate the amount of energy released when 1 kg of $_{ 92 }^{ 235 }{ U }$ undergoes fission reaction.

• 4)

Explain the results of Rutherford α-particle scattering experiment.

• 5)

Write the application of alpha decay in smoke detectors.

#### 12th Physics - Dual Nature of Radiation and Matter Five Marks Questions - by Sarojini - Tiruppur - Nov 04, 2019 - View & Read

• 1)

Calculate the energies of the photons associated with the following radiation:
(i) violet light of 413 nm
(ii) X-rays of 0.1 nm
(iii) radio waves of 10 m.

• 2)

A 150W lamp emits light of mean wavelength of 5500 A. If the efficiency is 12%, find out the number of photons emitted by the lamp in one second.

• 3)

How many photons of frequency 1014 Hz will make up 19.86 J of energy?

• 4)

When a 6000 A light falls on the cathode of a photo cell and produced photoemission. If a stopping potential of 0.8 V is required to stop emission of electron, then determine the
(i) frequency of the light
(ii) energy of the incident photon
(iii) work function of the cathode material
(iv) threshold frequency and
(v) net energy of the electron after it leaves the surface.

• 5)

A 3310 Å photon liberates an electron from a material with energy 3x10-19 J while another 5000 A photon ejects an electron with energy 0.972x 10-19 J from the same material. Determine' the value of Planck's constant and the threshold wavelength of the material.

#### 12th Physics - Optics Five Marks Questions - by Sarojini - Tiruppur - Nov 04, 2019 - View & Read

• 1)

If the distance D between an object and screen is greater than 4 times the focal length of a convex lens, then there are two positions of the lens for which images are formed on the screen. This method is called conjugate foci method. If d is the distance between the two positions of the lens, obtain the equation for focal length of the convex lens.

• 2)

A compound microscope has a magnifying power of 100 when the image is formed at infinity. The objective has a focal length of 0.5 cm and the tube length is 6.5 cm, What is the focal length of the eyepiece.

• 3)

Two light sources with amplitudes 5 units and 3 units respectively interfere with each other. Calculate the ratio of maximum and minimum intensities.

• 4)

Two light sources of equal amplitudes interfere with each other. Calculate the ratio of maximum and minimum intensities

• 5)

A monochromatic light of wavelength 5000 Å passes through a single slit producing diffraction pattern for the central maximum as shown in the figure. Determine the width of the slit.

#### 12th Physics - Semiconductor Electronics Three Marks Questions - by Sarojini - Tiruppur - Nov 04, 2019 - View & Read

• 1)

Explain the formation of PN junction diode. Discuss its V-I characteristics.

• 2)

Draw the circuit diagram' of a half wave rectifier and explain its working

• 3)

Explain the construction and working of a full wave rectifier.

• 4)

Write notes on Photodiode

• 5)

Explain the working principle of a solar cell. Mention its applications.

#### 12th Physics - Atomic and Nuclear physics Three Marks Questions - by Sarojini - Tiruppur - Nov 04, 2019 - View & Read

• 1)

Explain the J.J. Thomson experiment to determine the specific charge of electron

• 2)

Discuss the Millikan's oil drop experiment to determine the charge of an electron.

• 3)

Explain the idea of carbon dating.

• 4)

Discuss the process of nuclear fission and its properties.

• 5)

Find the
(i) angular momentum
(ii) velocity of the electron in the 5th orbit of hydrogen atom.
(h = 6.6 × 10–34 Js, m = 9.1 × 10–31 kg)

#### 12th Physics - Dual Nature of Radiation and Matter Three Marks Questions - by Sarojini - Tiruppur - Nov 04, 2019 - View & Read

• 1)

What do you mean by electron emission? Explain briefly various methods of electron emission.

• 2)

Briefly discuss the observations of Hertz. Hallwachs and Lenard.

• 3)

Explain the effect of potential difference on photoelectric current.

• 4)

Explain how frequency of incident light varies with stopping potential.

• 5)

List out the laws of photoelectric effect.

#### 12th Physics - Optics Three Marks Questions - by Sarojini - Tiruppur - Nov 04, 2019 - View & Read

• 1)

Obtain the equation for resultant intensity due to interference of light.

• 2)

Explain the Young's double slit experimental setup and obtain the equation for path difference.

• 3)

Discuss the interference in thin films and obtain the equations for constructive and destructive interference for transmitted and reflected light.

• 4)

Obtain the equation for of microscope.

• 5)

#### 12th Physics - Semiconductor Electronics Two Marks Questions - by Sarojini - Tiruppur - Nov 02, 2019 - View & Read

• 1)

Define electron motion in a semiconductor.

• 2)

Distinguish between Intrinsic and extrinsic semiconductors.

• 3)

What do you mean by doping?

• 4)

How electron-hole pairs are created in a semiconductor material?

• 5)

A diode is called as a unidirectional device. Explain.

#### 12th Physics - Atomic and Nuclear Physics Two Marks Questions - by Sarojini - Tiruppur - Nov 02, 2019 - View & Read

• 1)

What is meant by excitation energy?

• 2)

What is distance of dosest approach?

• 3)

Define impact parameter.

• 4)

Calculate the energy equivalent of 1 atomic mass unit.

• 5)

Give the physical meaning of binding energy per nucleon.

#### 12th Physics Dual Nature of Radiation and Matter Two Marks Question - by Sarojini - Tiruppur - Nov 02, 2019 - View & Read

• 1)

Why do metals have a large number of free electrons?

• 2)

Define work function of a metal. Give its unit.

• 3)

What is photoelectric effect?

• 4)

How does photocurrent vary with the intensity of the incident light?

• 5)

Give the definition of intensity of light and its unit.

#### 12th Physics - Optics Two Marks Questions - by Sarojini - Tiruppur - Nov 02, 2019 - View & Read

• 1)

What is Snell's window?

• 2)

Write a note on optical fibre.

• 3)

What are primary focus and secondary focus of convex lens?

• 4)

What are the sign conventions followed for lenses?

• 5)

What is Rayleigh's scattering?

#### 12th Physics - Recent Developments in Physics One Mark Questions with Answer - by Sarojini - Tiruppur - Nov 01, 2019 - View & Read

• 1)

The particle size of ZnO material is 30 nm. Based on the dimension it is classified as

• 2)

Which one of the following is the natural nanomaterial

• 3)

The blue print for making ultra durable synthetic material is mimicked from

• 4)

The method of making nanomaterial by assembling the atoms is called

• 5)

“Sky wax” is an application of nano product in the field of

#### 12th Physics - Semiconductor Electronics One Mark Questions with Answer - by Sarojini - Tiruppur - Nov 01, 2019 - View & Read

• 1)

The barrier potential of a silicon diode is approximately

• 2)

Doping a semiconductor results in

• 3)

A forward biased diode is treated as

• 4)

If a half –wave rectifi ed voltage is fed to a load resistor, which part of a cycle the load current will flow?

• 5)

The primary use of a zener diode is

#### 12th Physics - Atomic and Nuclear physics One Mark Questions with Answer - by Sarojini - Tiruppur - Nov 01, 2019 - View & Read

• 1)

Suppose an alpha particle accelerated by a potential of V volt is allowed to collide with a nucleus whose atomic number is Z, then the distance of closest approach of alpha particle to the nucleus is

• 2)

In a hydrogen atom, the electron revolving in the fourth orbit, has angular momentum equal to

• 3)

mirror of focal length of f and the maximum and minimum distance of

• 4)

The ratio between the first three orbits of hydrogen atom is

• 5)

The charge of cathode rays is

#### 12th Physics - Dual Nature of Radiation and Matter One Mark Questions with Answer - by Sarojini - Tiruppur - Nov 01, 2019 - View & Read

• 1)

The wavelength λe of an electron and λp of a photon of same energy E are related by

• 2)

In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would

• 3)

A particle of mass 3 × 10–6 g has the same wavelength as an electron moving with a velocity 6 10 × 6m s−1. The velocity of the particle is

• 4)

When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is $\frac{V}{4}$. The threshold wavelength for the metallic surface is

• 5)

If a light of wavelength 330 nm is incident on a metal with work function 3.55 eV, the electrons are emitted. Then the wavelength of the emitted electron is (Take h = 6.6 × 10–34 Js)

#### 12th Physics - Optics One Mark Questions with Answer - by Sarojini - Tiruppur - Nov 01, 2019 - View & Read

• 1)

The speed of light in an isotropic medium depends on,

• 2)

A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is,

• 3)

An object is placed in front of a convex mirror of focal length of f and the maximum and minimum distance of an object from the mirror such that the image formed is real and magnified.

• 4)

For light incident from air on a slab of refractive index 2, the maximum possible angle of refraction is,

• 5)

If the velocity and wavelength of light in air is Va and λa and that in water is Vw and λw, then the refractive index of water is,

#### 12th Standard Physics - Recent Developments in Physics Model Question Paper - by Sarojini - Tiruppur - Oct 30, 2019 - View & Read

• 1)

The particle size of ZnO material is 30 nm. Based on the dimension it is classified as

• 2)

Which one of the following is the natural nanomaterial

• 3)

The blue print for making ultra durable synthetic material is mimicked from

• 4)

The method of making nanomaterial by assembling the atoms is called

• 5)

“Sky wax” is an application of nano product in the field of

#### 12th Standard Physics - Communication Systems Model Question Paper - by Sarojini - Tiruppur - Oct 30, 2019 - View & Read

• 1)

The output transducer of the communication system converts the radio signal into ________.

• 2)

The signal is aff ected by noise in a communication system

• 3)

The variation of frequency of carrier wave with respect to the amplitude of the modulating signal is called _______.

• 4)

The internationally accepted frequency deviation for the purpose of FM broadcasts

• 5)

The frequency range of 3 MHz to 30 MHz is used for

#### 12th Standard Physics - Semiconductor Electronics Model Question Paper - by Sarojini - Tiruppur - Oct 30, 2019 - View & Read

• 1)

The barrier potential of a silicon diode is approximately

• 2)

Doping a semiconductor results in

• 3)

A forward biased diode is treated as

• 4)

If a half –wave rectifi ed voltage is fed to a load resistor, which part of a cycle the load current will flow?

• 5)

The primary use of a zener diode is

#### 12th Physics - Atomic and Nuclear Physics Model Question Paper - by Sarojini - Tiruppur - Oct 30, 2019 - View & Read

• 1)

In a hydrogen atom, the electron revolving in the fourth orbit, has angular momentum equal to

• 2)

mirror of focal length of f and the maximum and minimum distance of

• 3)

the nuclear radius of 27 al is 3.6 fermi, the approximate nuclear radius of 64Cu is

• 4)

The nucleus is approximately spherical in shape. Then the surface area of nucleus having mass number A varies as

• 5)

Mp denotes the mass of the proton and Mn denotes mass of a neutron. A given nucleus of binding energy B, contains Z protons and N neutrons. The mass M(N,Z) of the nucleus is given by(where c is the speed of light)

#### 12th Physics - Dual Nature of Radiation and Matter Model Question Paper - by Sarojini - Tiruppur - Oct 30, 2019 - View & Read

• 1)

The wavelength λe of an electron and λp of a photon of same energy E are related by

• 2)

In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would

• 3)

A particle of mass 3 × 10–6 g has the same wavelength as an electron moving with a velocity 6 10 × 6m s−1. The velocity of the particle is

• 4)

When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is $\frac{V}{4}$. The threshold wavelength for the metallic surface is

• 5)

If a light of wavelength 330 nm is incident on a metal with work function 3.55 eV, the electrons are emitted. Then the wavelength of the emitted electron is (Take h = 6.6 × 10–34 Js)

#### 12th Physics - Optics Model Question Paper - by Sarojini - Tiruppur - Oct 30, 2019 - View & Read

• 1)

For light incident from air on a slab of refractive index 2, the maximum possible angle of refraction is,

• 2)

If the velocity and wavelength of light in air is Va and λa and that in water is Vw and λw, then the refractive index of water is,

• 3)

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index,

• 4)

The radius of curvature of curved surface at a thin planoconvex lens is 10 cm and the refractive index is 1.5. If the plane surface is silvered, then the focal length will be,

• 5)

A plane glass is placed over a various coloured letters (violet, green, yellow, red) The letter which appears to be raised more is,

#### 12th Standard Physics - Term II Model Question Paper - by Pavithra - Karaikkudi - Oct 29, 2019 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 3)

Two wires of A and B with circular cross section made up of the same material with equal lengths. Suppose RA = 3 RB, then what is the ratio of radius of wire A to that of B?

• 4)

In Joule’s heating law, when I and t are constant, if the H is taken along the y axis and I2 along the x axis, the graph is

• 5)

Th ree wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. Th ey are placed in a uniform magnetic fi eld and same electric current is passed through them. Which of the following loop confi guration will experience greater torque ?

#### 12th Standard Physics - Electromagnetic waves Model Question Paper - by Pavithra - Karaikkudi - Oct 09, 2019 - View & Read

• 1)

The dimension of $\frac { 1 }{ { \mu }_{ 0 }{ \varepsilon }_{ 0 } }$ is

• 2)

Which of the following are false for electromagnetic waves

• 3)

Th e electric and the magnetic field, associated with an electromagnetic wave, propagating along X axis can be represented by

• 4)

In an electromagnetic wave in free space the rms value of the electric fi eld is 3 V m−1. The peak value of the magnetic field is

• 5)

Which of the following is an electromagnetic wave?

#### 12th Standard Physics - Electromagnetic Induction and Alternating Current Model Question Paper - by Pavithra - Karaikkudi - Oct 01, 2019 - View & Read

• 1)

Th e fl ux linked with a coil at any instant t is given by $\Phi$B =10t2−50t+ 250 . The induced emf at t = 3s is

• 2)

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

• 3)

In an electrical circuit, R, L, C and AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and current in the circuit is $\frac{\pi}{3}$. Instead, if C is removed from the circuit, the phase difference is again  $\frac{\pi}{3}$.  The power factor of the circuit is

• 4)

An inductor 20 mH, a capacitor 50 μF and a resistor 40 Ω are connected in series across a source of emf v = 10 sin 340 t. The power loss in AC circuit is

• 5)

$\frac{20}{\pi^2}H$inductor is connected to a capacitor of capacitance C. The value of C in order to impart maximum power at 50 Hz is

#### 12th Standard Physics - Magnetism and Magnetic Effects of Electric Current Model Question Paper - by Pavithra - Karaikkudi - Oct 01, 2019 - View & Read

• 1)

A circular coil of radius 5 cm and 50 turns carries a current of 3 ampere. The magnetic dipole moment of the coil is

• 2)

A wire of length l carries a current I along the Y direction and magnetic field is given by $\vec { B } =\frac { \beta }{ \sqrt { 3 } } =(\hat { i } +\hat { j } +\hat { k } )T.$ The magnitude of Lorentz force acting on the wire is

• 3)

The vertical component of Earth’s magnetic field at a place is equal to the horizontal component. What is the value of angle of dip at this place?

• 4)

The most suitable metal for permanent magnet is

• 5)

When current is doubled deflection is also doubled in

#### 12th Standard Physics - Electromagnetic Waves Three Marks Questions - by Sarojini - Tiruppur - Sep 30, 2019 - View & Read

• 1)

The relative magnetic permeability of the medium is 2.5 and the relative electrical permittivity of the medium is 2.25. Compute the refractive index of the medium.

• 2)

Write down Maxwell equations in integral form.

• 3)

Write down the properties of electromagnetic waves.

• 4)

Discuss the source of electromagnetic wave.

• 5)

What is emission spectra?. Give their types.

#### 12th Standard Physics - Electromagnetic Induction and Alternating Current Three Marks Questions - by Sarojini - Tiruppur - Sep 30, 2019 - View & Read

• 1)

A cylindrical bar magnet is kept along the axis of a circular solenoid. If the magnet is rotated about its axis, find out whether an electric current is induced in the coil.

• 2)

A closed coil of 40 turns and of area 200 cm2, is rotated in a magnetic field of flux density 2 Wb m-2. It rotates from a position where its plane makes an angle of 30o with the field to a position perpendicular to the field in a time 0.2 sec. Find the magnitude of the emf induced in the coil due to its rotation.

• 3)

A straight conducting wire is dropped horizontally from a certain height with its length along east – west direction. Will an emf be induced in it? Justify your answer.

• 4)

A conducting rod of length 0.5 m falls freely from the top of a building of height 7.2 m at a place in Chennai where the horizontal component of Earth’s magnetic field is 40378.7 nT. If the length of the rod is perpendicular to Earth’s horizontal magnetic field, find the emf induced across the conductor when the rod is about to touch the ground. [Take g = 10 m s-2]

• 5)

A copper rod of length l rotates about one of its ends with an angular velocity ω in a magnetic field B as shown in the figure. The plane of rotation is perpendicular to the field. Find the emf induced between the two ends of the rod.

#### 12th Standard Physics - Magnetism and Magnetic Effects of Electric Current Three Marks Questions - by Sarojini - Tiruppur - Sep 30, 2019 - View & Read

• 1)

The repulsive force between two magnetic poles in air is 9 x 10-3 N. If the two poles are equal in strength and are separated by a distance of 10 cm, calculate the pole strength of each pole.

• 2)

A short bar magnet has a magnetic moment of 0.5 J T-1. Calculate magnitude and
direction of the magnetic field produced by the bar magnet which is kept at a distance
of 0.1 m from the center of the bar magnet along
(a) axial line of the bar magnet and
(b) normal bisector of the bar magnet.

• 3)

Compute the intensity of magnetisation of the bar magnet whose mass, magnetic moment and density are 200 g, 2 A m2 and 8 g cm-3, respectively.

• 4)

Using the relation $\overset { \rightarrow }{ B } =\mu _{ ° }(\overset { \rightarrow }{ H+ } \overset { \rightarrow }{ M } )$ show that ${ x }_{ m }={ \mu }_{ r }-{ 1 }$

• 5)

The magnetic field shown in the figure is due to the current carrying wire. In which
direction does the current flow in the wire?.

#### 12th Physics - Current Electricity Three Marks Questions - by Sarojini - Tiruppur - Sep 30, 2019 - View & Read

• 1)

If an electric field of magnitude 570 N C-1, is applied in the copper wire, find the acceleration experienced by the electron.

• 2)

A copper wire of cross-sectional area 0.5 mm2 carries a current of 0.2 A. If the free electron density of copper is 8.4 × 1028 m-3 then compute the drift velocity of free electrons.

• 3)

A potential difference across 24 Ω resistor is 12 V. What is the current through the resistor?

• 4)

Describe the microscopic model of current and obtain general form of Ohm’s law.

• 5)

Explain the equivalent resistance of a series and parallel resistor network

#### 12th Physics - Electrostatics Three Marks Questions - by Sarojini - Tiruppur - Sep 30, 2019 - View & Read

• 1)

Calculate the electrostatic force and gravitational force between the proton and the electron in a hydrogen atom. They are separated by a distance of 5.3 × 10-11 m. The magnitude of charges on the electron and proton are 1.6 × 10-19 C. Mass of the electron is me = 9.1 × 10-31 kg and mass of proton is mp = 1.6 × 10-27 kg.

• 2)

Consider four equal charges q1,q2, q3 and q4 = q = +1μC located at four different points on a circle of radius 1m, as shown in the figure. Calculate the total force acting on the charge q1 due to all the other charges.

• 3)

Obtain the expression for capacitance for a parallel plate capacitor.

• 4)

Obtain the expression for energy stored in the parallel plate capacitor.

• 5)

Explain in detail the effect of a dielectric placed in a parallel plate capacitor.

#### 12th Physics - Current Electricity Model Question Paper - by Pavithra - Karaikkudi - Sep 27, 2019 - View & Read

• 1)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 2)

Two wires of A and B with circular cross section made up of the same material with equal lengths. Suppose RA = 3 RB, then what is the ratio of radius of wire A to that of B?

• 3)

The temperature coefficient of resistance of a wire is 0.00125 per °C. At 300 K, its resistance is 1 Ω. The resistance of the wire will be 2 Ω at

• 4)

In Joule’s heating law, when I and t are constant, if the H is taken along the y axis and I2 along the x axis, the graph is

• 5)

The temperature co-efficient of resistance for alloys is

#### 12th Standard Physics - Electrostatics Model Question Paper - by Pavithra - Karaikkudi - Sep 27, 2019 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 3)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 4)

Two metallic spheres of radii 1 cm and 3 cm are given charges of -1 x 10-2 C and 5 x 10-2 C respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is

• 5)

The electrostatic force obeys _______.

#### 12th Physics - Term 1 Model Question Paper - by Pavithra - Karaikkudi - Sep 21, 2019 - View & Read

• 1)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 2)

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

• 3)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 4)

A non-conducting charged ring of charge q, mass m and radius r is rotated with constant angular speed ω. Find the ratio of its magnetic moment with angular momentum is

• 5)

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. Th e co-efficient of self-induction of the coil is

#### 12th Physics - Term 1 Five Mark Model Question Paper - by Sarojini - Tiruppur - Sep 16, 2019 - View & Read

• 1)

When two objects are rubbed with each other, approximately a charge of 50 nC can be produced in each object. Calculate the number of electrons that must be transferred to produce this charge.

• 2)

Two electric bulbs marked 20 W – 220 V and 100 W – 220 V are connected in series to 440 V supply. Which bulb will be fused?

• 3)

What is the value of x when the Wheatstone’s network is balanced?
P = 500 Ω, Q = 800 Ω, R = x + 400, S = 1000 Ω

• 4)

A cell supplies a current of 0.9 A through a 2 Ω resistor and a current of 0.3 A through a 7 Ω resistor. Calculate the internal resistance of the cell.

• 5)

In a plane Electromagnetic wave the electric field oscillates sinusoidally at a frequency of 1.5 X 1010Hz & amplitude 36 Vm-1.
(i) What is the wavelength of a wave?
(ii) What the amplitude of the oscillating magnetic field?
(iii) Straight the average energy density of the electric field $\left( \overrightarrow { E } \right)$ , is equal to average energy density of the magnetic field $\left( \overrightarrow { B } \right)$

#### 12th Physics - Electromagnetic Waves Two Marks Questions - by Sarojini - Tiruppur - Sep 16, 2019 - View & Read

• 1)

What is displacement current?

• 2)

What are electromagnetic waves?

• 3)

Write down the integral form of modified Ampere’s circuital law.

• 4)

Explain the concept of intensity of electromagnetic waves.

• 5)

What is meant by Fraunhofer lines?

#### 12th Physics - Electromagnetic Induction and Alternating Current Two Marks Questions - by Sarojini - Tiruppur - Sep 16, 2019 - View & Read

• 1)

How is Eddy current produced? How do they flow in a conductor?

• 2)

Mention the ways of producing induced emf.

• 3)

Give the principle of AC generator.

• 4)

List out the advantages of stationary armature-rotating field system of AC generator.

• 5)

What do you mean by resonant frequency?

#### 12th Physics - Magnetism and Magnetic Effects of Electric Current Two Marks Questions - by Sarojini - Tiruppur - Sep 16, 2019 - View & Read

• 1)

What is meant by magnetic induction?

• 2)

Define magnetic flux.

• 3)

What is magnetic susceptibility?

• 4)

State Biot-Savart’s law.

• 5)

What is meant by hysteresis?

#### 12th Physics - Current Electricity Two Marks Questions - by Sarojini - Tiruppur - Sep 16, 2019 - View & Read

• 1)

What is superconductivity?

• 2)

What is electric power and electric energy?

• 3)

State Kirchhoff’s voltage rule.

• 4)

State the principle of potentiometer.

• 5)

What is Peltier effect?

#### 12th Physics Chapter 1 Electrostatics Two Marks Questions - by Sarojini - Tiruppur - Sep 16, 2019 - View & Read

• 1)

What is meant by quantisation of charges?

• 2)

Write down Coulomb’s law in vector form and mention what each term represents.

• 3)

What is mean by ‘Electric field lines’?

• 4)

The electric field lines never intersect Justify.

• 5)

What is an equipotential surface?

#### 12th Physics Quarterly Model Question Paper - by Sarojini - Tiruppur - Sep 13, 2019 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 3)

An uncharged metal sphere is placed between two equal and oppositely charged metal plates. The nature of lines of force will be

• 4)

The magnitude of electric dipole moment of water molecule is

• 5)

Which of the following statement on equipotential surface is wrong?

#### 12th Standard Physics - Electromagnetic waves Book Back Questions - by Sarojini - Tiruppur - Sep 03, 2019 - View & Read

• 1)

What is displacement current?

• 2)

What are electromagnetic waves?

• 3)

What is meant by Fraunhofer lines?

• 4)

The relative magnetic permeability of the medium is 2.5 and the relative electrical permittivity of the medium is 2.25. Compute the refractive index of the medium.

• 5)

Discuss briefly the experiment conducted by Hertz to produce and detect electromagnetic spectrum.

#### 12th Standard Physics - Magnetism and Magnetic Effects of Electric Current Book Back Questions - by Sarojini - Tiruppur - Sep 02, 2019 - View & Read

• 1)

Th e force experienced by a particle having mass m and charge q accelerated through a potential diff erence V when it is kept under perpendicular magnetic field $\vec { B }$ is

• 2)

Th ree wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. Th ey are placed in a uniform magnetic fi eld and same electric current is passed through them. Which of the following loop confi guration will experience greater torque ?

• 3)

A non-conducting charged ring of charge q, mass m and radius r is rotated with constant angular speed ω. Find the ratio of its magnetic moment with angular momentum is

• 4)

The vertical component of Earth’s magnetic field at a place is equal to the horizontal component. What is the value of angle of dip at this place?

• 5)

A simple pendulum with charged bob is oscillating with time period T and let θ be the angular displacement. If the uniform magnetic field i switched ON in a direction perpendicular to the plane of oscillation then

#### 12th Standard Physics - Electromagnetic Induction and Alternating Current Book Back Questions - by Sarojini - Tiruppur - Sep 02, 2019 - View & Read

• 1)

Th e fl ux linked with a coil at any instant t is given by $\Phi$B =10t2−50t+ 250 . The induced emf at t = 3s is

• 2)

A circular coil with a cross-sectional area of 4 cm2 has 10 turns. It is placed at the centre of a long solenoid that has 15 turns/cm and a cross-sectional area of 10 cm2. The axis of the coil coincides with the axis of the solenoid. What is their mutual inductance?

• 3)

An inductor 20 mH, a capacitor 50 μF and a resistor 40 Ω are connected in series across a source of emf v = 10 sin 340 t. The power loss in AC circuit is

• 4)

In an oscillating LC circuit, the maximum charge on the capacitor is Q. The charge on the capacitor when the energy is stored equally between the electric and magnetic fields is

• 5)

$\frac{20}{\pi^2}H$inductor is connected to a capacitor of capacitance C. The value of C in order to impart maximum power at 50 Hz is

#### 12th Standard Physics Chapter 2 Current Electricity Book Back Questions - by Sarojini - Tiruppur - Aug 31, 2019 - View & Read

• 1)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 2)

What is the value of resistance of the following resistor?

• 3)

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, the resistance of a 60W bulb for use in USA will be

• 4)

The temperature coefficient of resistance of a wire is 0.00125 per °C. At 300 K, its resistance is 1 Ω. The resistance of the wire will be 2 Ω at

• 5)

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

#### 12th Standard Physics Unit 1 Electrostatics Book Back Questions - by Sarojini - Tiruppur - Aug 30, 2019 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 3)

The total electric fl ux for the following closed surface which is kept inside water

• 4)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

• 5)

Rank the electrostatic potential energies for the given system of charges in increasing order.

#### 12th Standard Physics Chapter 4 Electromagnetic Induction and Alternating Current One Mark Question with Answer Key - by Sarojini - Tiruppur - Aug 29, 2019 - View & Read

• 1)

In a series resonant RLC circuit, the voltage across 100 Ω resistor is 40 V. The resonant frequency ω is 250 rad/s. If the value of C is 4 μF, then the voltage across L is

• 2)

An inductor 20 mH, a capacitor 50 μF and a resistor 40 Ω are connected in series across a source of emf v = 10 sin 340 t. The power loss in AC circuit is

• 3)

The instantaneous values of alternating current and voltage in a circuit are $i=\frac { 1 }{ \sqrt { 2 } } sin\left( 100\pi t \right)$ A and v=$=\frac { 1 }{ \sqrt { 2 } } sin\left( 100\pi t+\frac { \pi }{ 3 } \right) V.$The average power in watts consumed in the circuit is

• 4)

In an oscillating LC circuit, the maximum charge on the capacitor is Q. The charge on the capacitor when the energy is stored equally between the electric and magnetic fields is

• 5)

$\frac{20}{\pi^2}H$inductor is connected to a capacitor of capacitance C. The value of C in order to impart maximum power at 50 Hz is

#### 12th Standard Physics Chapter 3 Magnetism and Magnetic Effects of Electric Current One Mark Question and Answer - by Sarojini - Tiruppur - Aug 29, 2019 - View & Read

• 1)

The BH curve for a ferromagnetic material is shown in the figure. The material is placed inside a long solenoid which contains 1000 turns/cm. The current that should be passed in the solenonid to demagnetize the ferromagnet completely is

• 2)

Two short bar magnets have magnetic moments 1.20 Am2 and 1.00 Am2 respectively. They are kept on a horizontal table parallel to each other with their north poles pointing towards the south. They have a common magnetic equator and are separated by a distance of 20.0 cm. The value of the resultant horizontal magnetic induction at the mid-point O of the line joining their centers is (Horizontal components of Earth’s magnetic induction is 3.6 x 10-5 Wb m-2 )

• 3)

The vertical component of Earth’s magnetic field at a place is equal to the horizontal component. What is the value of angle of dip at this place?

• 4)

A flat dielectric disc of radius R carries an excess charge on its surface. The surface charge density is σ. The disc rotates about an axis perpendicular to its plane passing through the center with angular velocity ω. Find the magnitude of the torque on the disc if it is placed in a uniform magnetic field whose strength is B which is directed perpendicular to the axis of rotation

• 5)

A simple pendulum with charged bob is oscillating with time period T and let θ be the angular displacement. If the uniform magnetic field i switched ON in a direction perpendicular to the plane of oscillation then

#### 12th Standard Physics - Current Electricity One Mark Question and Answer - by Sarojini - Tiruppur - Aug 28, 2019 - View & Read

• 1)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 2)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 3)

When 'n' resistors of equal resistance (R) are connected in series and in parallel respectively,then the ratio of their effective resistance is

• 4)

Which of the following has negative temperature coefficient of resistance?

• 5)

The temperature co-efficient of resistance for alloys is

#### 12th Standard Physics Unit 1 Electrostatics One Mark Question and Answer - by Sarojini - Tiruppur - Aug 27, 2019 - View & Read

• 1)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 2)

The total electric fl ux for the following closed surface which is kept inside water

• 3)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 4)

The value of constant 'K' in coulomb law is

• 5)

The electrostatic force is always greater in magnitude than gravitational force for_________ object.

#### 12th Standard Chapter 5 Electromagnetic Waves One Mark Question Paper with Answer - by Sarojini - Tiruppur - Aug 27, 2019 - View & Read

• 1)

Consider an oscillator which has a charged particle and oscillates about its mean position with a frequency of 300 MHz. Th e wavelength of electromagnetic waves produced by this oscillator is

• 2)

Th e electric and the magnetic field, associated with an electromagnetic wave, propagating along X axis can be represented by

• 3)

In an electromagnetic wave in free space the rms value of the electric fi eld is 3 V m−1. The peak value of the magnetic field is

• 4)

Electromagnetic waves are produced by

• 5)

Which of the following electromagnetic waves has the highest frequency?

#### 12th Standard Physics Chapter 4 Electromagnetic Induction and Alternating Current One Mark Question with Answer Key - by Sarojini - Tiruppur - Aug 27, 2019 - View & Read

• 1)

Th e fl ux linked with a coil at any instant t is given by $\Phi$B =10t2−50t+ 250 . The induced emf at t = 3s is

• 2)

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. Th e co-efficient of self-induction of the coil is

• 3)

A step-down transformer reduces the supply voltage from 220 V to 11 V and increase the current from 6 A to 100 A. Then its efficiency is

• 4)

In a series RL circuit, the resistance and inductive reactance are the same. Then the phase difference between the voltage and current in the circuit is

• 5)

An inductor 20 mH, a capacitor 50 μF and a resistor 40 Ω are connected in series across a source of emf v = 10 sin 340 t. The power loss in AC circuit is

#### 12th Physics Unit 3 Magnetism and Magnetic Effects of Electric Current One Mark Question with Answer Key - by Sarojini - Tiruppur - Aug 26, 2019 - View & Read

• 1)

A circular coil of radius 5 cm and 50 turns carries a current of 3 ampere. The magnetic dipole moment of the coil is

• 2)

A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively.
The magnetic induction at the center of the spiral is

• 3)

A wire of length l carries a current I along the Y direction and magnetic field is given by $\vec { B } =\frac { \beta }{ \sqrt { 3 } } =(\hat { i } +\hat { j } +\hat { k } )T.$ The magnitude of Lorentz force acting on the wire is

• 4)

The vertical component of Earth’s magnetic field at a place is equal to the horizontal component. What is the value of angle of dip at this place?

• 5)

When current is doubled deflection is also doubled in

#### 12th Physics Chapter 2 Current Electricity One Mark Question Paper - by Sarojini - Tiruppur - Aug 24, 2019 - View & Read

• 1)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 2)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 3)

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, the resistance of a 60W bulb for use in USA will be

• 4)

In Joule’s heating law, when I and t are constant, if the H is taken along the y axis and I2 along the x axis, the graph is

• 5)

Which of the following has negative temperature coefficient of resistance?

#### 12th Physics Electrostatics One Mark Question Paper - by Sarojini - Tiruppur - Aug 23, 2019 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

Which charge configuration produces a uniform electric field?

• 3)

If voltage applied on a capacitor is increased from V to 2V, choose the correct conclusion

• 4)

Two metallic spheres of radii 1 cm and 3 cm are given charges of -1 x 10-2 C and 5 x 10-2 C respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is

• 5)

Based on Franklin's convention amber rods are_________.

#### 12th Physics Quarterly Exam Model Two Marks Question Paper - by Sarojini - Tiruppur - Aug 20, 2019 - View & Read

• 1)

What is meant by quantisation of charges?

• 2)

Give the relation between electric field and electric potential.

• 3)

Give a comparison of electrical and gravitional forces?

• 4)

The graph shows the variation of volatage 'v' across the plates of two capacitors A & Bversus increase of charge 'Q' stored on them. Which of the two capacitors has higher capacitance?
Give reason.

• 5)

State microscopic form of Ohm’s law.

#### Plus Two Quarterly Exam Model One Mark Question Paper - by Sarojini - Tiruppur - Aug 05, 2019 - View & Read

• 1)

Which charge configuration produces a uniform electric field?

• 2)

An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

• 3)

Two points A and B are maintained at a potential of 7 V and -4 V respectively. The work done in moving 50 electrons from A to B is

• 4)

In electrostatics if the charges are in motion, another force named __________ comes into play in addition to coulomb force

• 5)

The value of constant 'K' in coulomb law is

#### Plus 2 Physics Chapter 5 Electromagnetic Waves Model Question Paper - by Sarojini - Tiruppur - Aug 03, 2019 - View & Read

• 1)

The dimension of $\frac { 1 }{ { \mu }_{ 0 }{ \varepsilon }_{ 0 } }$ is

• 2)

During the propagation of electromagnetic waves in a medium

• 3)

The EM waves do not transport

• 4)

Which EM waves are used in medicine to destroy cancer cells?

• 5)

A magnetic field is produced by

#### 12th Standard Physics First Mid Term Model Question Paper - by Sarojini - Tiruppur - Aug 01, 2019 - View & Read

• 1)

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric fl ux through each Gaussian surface in increasing order.

• 2)

The value of constant 'K' in coulomb law is

• 3)

For a large charge accumulation, the end of the conductor should have larger curvature that is_________.

• 4)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 5)

Th ree wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. Th ey are placed in a uniform magnetic fi eld and same electric current is passed through them. Which of the following loop confi guration will experience greater torque ?

#### 11th Standard Physics Chapter 4 Electromagnetic Induction and Alternating Current Important Question Paper - by Sarojini - Tiruppur - Jul 30, 2019 - View & Read

• 1)

Th e fl ux linked with a coil at any instant t is given by $\Phi$B =10t2−50t+ 250 . The induced emf at t = 3s is

• 2)

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. Th e co-efficient of self-induction of the coil is

• 3)

A circular coil with a cross-sectional area of 4 cm2 has 10 turns. It is placed at the centre of a long solenoid that has 15 turns/cm and a cross-sectional area of 10 cm2. The axis of the coil coincides with the axis of the solenoid. What is their mutual inductance?

• 4)

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

• 5)

A step-down transformer reduces the supply voltage from 220 V to 11 V and increase the current from 6 A to 100 A. Then its efficiency is

#### 12th Standard Physics Chapter 3 Magnetism and Magnetic Effects of Electric Current Important Question Paper - by Sarojini - Tiruppur - Jul 26, 2019 - View & Read

• 1)

The magnetic fi eld at the center O of the following current loop is

• 2)

A circular coil of radius 5 cm and 50 turns carries a current of 3 ampere. The magnetic dipole moment of the coil is

• 3)

A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively.
The magnetic induction at the center of the spiral is

• 4)

Four wires each of length 2m are bent into four loops P, Q, R and S and then suspended into uniform magnetic field as shown in the figure same current is passed in each loop. On which loop the couple will be the highest?

• 5)

A current carrying conductor is associated with

#### 12th Physics Unit 2 Model Question Paper - by Sarojini - Tiruppur - Jul 24, 2019 - View & Read

• 1)

A toaster operating at 240 V has a resistance of 120 Ω. Th e power is

• 2)

A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of diff erent colours for its identifi cation. Th e colour code sequence will be

• 3)

Two wires of A and B with circular cross section made up of the same material with equal lengths. Suppose RA = 3 RB, then what is the ratio of radius of wire A to that of B?

• 4)

A wire connected to a power supply of 230 V has power dissipation P1. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case power dissipation is P2. The ratio $\frac{P_2}{P_1}$ is

• 5)

When 'n' resistors of equal resistance (R) are connected in series and in parallel respectively,then the ratio of their effective resistance is

#### 12th Physics - Chapter 1 Electrostatics Important Question Paper - by Sarojini - Tiruppur - Jul 18, 2019 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 3)

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric fl ux through each Gaussian surface in increasing order.

• 4)

The total electric fl ux for the following closed surface which is kept inside water

• 5)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

#### 12th Standard Physics Electrostatics Important Question Paper - by Ravikumar - Jul 18, 2019 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

The total electric fl ux for the following closed surface which is kept inside water

• 3)

The electrostatic force is always greater in magnitude than gravitational force for_________ object.

• 4)

The relative permittivity of water is _______.

• 5)

An isolated metal sphere of radius 'r' is given a charge' q'. The potential energy of the sphere is

#### twelfth standard english medium important multiple choice questions in physics - by Ravikumar - Jun 27, 2019 - View & Read

• 1)

For sharper edge, the ______ is greater. This principle is used in Lightning arrestor

• 2)

For continuous charge distributions, _____ methods can be used.

• 3)

For a large charge accumulation, the end of the conductor should have larger curvature that is_________.

• 4)

Relative permittivity (εr) is also known as ________

• 5)

The energy stored per unit volume of space is defined as________.

#### frequently asked multiple choice questions twelfth standard english medium physics - by Ravikumar - Jun 27, 2019 - View & Read

• 1)

A charge Q is placed at the corner of a cube. The electric flux through all the six faces of the cube is

• 2)

Which graph shows the variation of electric field E due to a hollow spherical conductor of radius R as a function of distance from the centre of the sphere?

• 3)

In a hollow spherical shell potential (V) changes with respect to distance (r) from centre.
$\left[ { V }_{ inside }=\frac { Q }{ 4\pi { \varepsilon }_{ 0 }R } r\le R,\quad { V }_{ outside }=\frac { Q }{ 4\pi { \varepsilon }_{ 0 }r } r\ge R,V\alpha \frac { 1 }{ r } \right]$

• 4)

What physical quantities may X and Y represent? [Y represents the first mentioned quantity].

• 5)

During charging a capacitor variation of potential V of the capacitor with time t as shown a

#### Most important one mark questions physics chapter one - by Ravikumar - Jun 27, 2019 - View & Read

• 1)

If C is the capacitance of an air filled capacitor and C is the capacitance of dielectric filled capacitor, then

• 2)

The capacitance of a parallel plate capacitor increases from 5μf of 50μf when a dielectric is filled between the plates. The permitivity of the dielectric is

• 3)

An electric dipole placed at an angle in a nonuniform electric field experiences

• 4)

Two copper spheres A and B of same size are charged to same potential. A is hollow and B is solid. Which of the two holds more charge?

• 5)

A bird sitting an a high power line

#### Centum multiple choice questions Chepter one Physics - by Ravikumar - Jun 27, 2019 - View & Read

• 1)

The expression for the electric field due to a surface of total charge 'Q' is given by

• 2)

The dipole is called point dipole when the distance

• 3)

The magnitude of torque on dipole is maximum if

• 4)

The magnitude of electric dipole moment of water molecule is

• 5)

The expression for electric potentid difference is

#### New syllabus creative multiple choice questions physics - by Ravikumar - Jun 27, 2019 - View & Read

• 1)

The figure shows tow parallel equipotential surface A and B kept at a small distance 'r' a part from each other. A point change of Q coulomb is taken from the surface A to B. The amount of net work done will be

• 2)

The given figure is a plot of lines of force due to two charges q1 & q2 find out the sign of charges

• 3)

An uncharged metal sphere is placed between two equal and oppositely charged metal plates. The nature of lines of force will be

• 4)

An isolated metal sphere of radius 'r' is given a charge' q'. The potential energy of the sphere is

• 5)

In a hydrogen atom the electron revolves around the proton in an orbit of 0.53 $\mathring { A }$. The potential produced by the electron on the nuleus is

#### Physics chapter one new syllabus Important one mark questions - by Ravikumar - Jun 27, 2019 - View & Read

• 1)

Two identical point charges of magnitude –q are fi xed as shown in the fi gure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement

• 2)

Which charge configuration produces a uniform electric field?

• 3)

An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

• 4)

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric fl ux through each Gaussian surface in increasing order.

• 5)

Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be