### 12th Standard EM Physics Study material & Free Online Practice Tests - View Model Question Papers with Solutions for Class 12 Session 2019 - 2020 TN Stateboard [ Chapter , Marks , Book Back, Creative & Term Based Questions Papers - Syllabus, Study Materials, MCQ's Practice Tests etc..]

#### 12th standard Physics full portion important One Mark Questions - 2020 - by Sarojini - Tiruppur - 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 - 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 - 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 - 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 - 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 - 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 - 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)

What is a wavefront?

• 5)

How does wavefront division provide coherent sources?

#### 12th Physics Electromagnetic Waves - Two Marks Study Materials - by 8682895000 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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)

Obtain the equations for constructive and destructive interference for transmitted and reflected waves in thin films.

• 4)

Obtain the equation for of microscope.

• 5)

#### 12th Physics - Semiconductor Electronics Two Marks Questions - by Sarojini - Tiruppur - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 Practice Question Paper 2019-2020 - by Physics English Medium - New syllabus 2019 - 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)

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

• 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 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

#### 12th Standard Physics - Electromagnetic Induction and Alternating Current Model Question Paper - by Pavithra - Karaikkudi - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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?

### TN Stateboard Education Study Materials

The His

#### 12th Stateboard Physics 2019 - 2020 Academic Monthly Syllabus - by Sarojini - Tiruppur Aug 02, 2019 Aug 02, 2019

Physics 2019 - 2020 Academic Monthly Syllabus

### TN Stateboard Updated Class 12th Physics Syllabus

#### Electrostatics

Introduction - Coulomb's Law - Electric Field and Electric Field Lines - Electric dipole and Its Properties - Electrostatic Potential and Potential Energy - Gauss Law and Its Applications - Electrostatics of Conductors and Dielectrics - Capacitors and Capacitance - Distribution of Charges In A Conductor and Action At Points

#### Current Electricity

Introduction - Electric Current - Ohm’s Law - Energy and Power In Electrical Circuits - Electric Cells and Batteries - Kirchhoff ’s Law - Heating Effect of Electric Current - Thermoelectric Current

#### Magnetism and magnetic effects of electric current

Introduction of Magnetism - Coulomb's Inverse Square Law of Magnetism - Torque Acting On a Bar Magnet In Uniform Magnetic Field - Magnetic Properties - Classification of Magnetic Materials - Hysteresis - Magnetic Effects of Current - Biot - Savart Law - Ampere’s Circuital Law - Lorentz Force - Torque On a Current Loop

#### Electromagnetic Induction And Alternating Current

Introduction - Electromagnetic Induction - Eddy currents - Self-Induction - Methods of Producing Induced EMF - AC Generator - Transformer - Alternating Current - Power
In AC Circuits - Oscillations In LC Circuits

#### Electromagnetic waves

Introduction - Electromagnetic Waves - Types of Spectrum-Emission and Absorption Spectrum-Fraunhofer Lines

#### TN StateboardStudy Material - Sample Question Papers with Solutions for Class 12 Session 2019 - 2020

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