Physics Question Papers & Study Material

12th CBSE Physics Electrostatics Model Question Paper 2 - by Sharma - Kochi Aug 20, 2019 - View & Download

1)
At a particular point, electric field depends upon
2)
Electric field due to a single charge is
3)
When an electric dipole is held at an angle in a uniform electric field, the net force F and torque \(\tau\) on the dipole are
4)
Electrostatic potential V at a point, distant r from a charge q varies as
5)
1 G eV = x eV, where x is

12th Standard CBSE Physics Communication Systems Model Question Paper - by Sharma - Kochi Aug 19, 2019 - View & Download

1)
A 100m long antenna is mounted on a 500 m tall building. The complex can become a transmission tower for waves with \(\lambda \).
2)
Out of the following, which is not an essential element of a communication system?
3)
The frequency band of FM broadcast is
4)
The correct relation between plasma frequency v of a radio wave and electron density N of the ionosphere layer is
5)
The fraction of world's human population using the services of internet is

12th CBSE Physics Electronic Devices Model Question Paper - by Sharma - Kochi Aug 12, 2019 - View & Download

1)
The conduction band in a solid is partially filled at 0 k.The solid sample is
2)
In an n-type semiconductor,the Fermi level lies 0.3 e V below the conduction band at 300 k.If the temperature is increased to 330 k ,where does the new position of the Fermi level lie?
3)
A p-type semiconductor is obtained by doping silicon with
4)
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 2480 nm is incident on it.The band gap (in e V) for the semiconductor is
5)
The transistor is operated in common emitter configuration at \(\mu A\)to 200 \(\mu A\)produces a change in the collector current from 5 mA to 10 mA.The current gain is

12th Standard CBSE Physics Unit 8 Atoms and Nuclei Model Question Paper - by Sharma - Kochi Aug 05, 2019 - View & Download

1)
Taking the Bohr radius as a₀=53pm, the radius of Li⁺⁺ ion its ground state, on the basis of Boh''s model, will be about
2)
O₂ molecule consists of two oxygen atoms.In the molecule, nuclear force between the nuclei of the two atoms
3)
Consider aiming a beam of free electrons towards free protons.When they scatter, an electron and a proton cannot combine to produce a H-atom,
4)
For the ground state, the electron in the H-atom has an angular momentum = h, according to the simple Bohr model. Angular momentum is a vector and hence there will be infinitely many orbits with the vector pointing in all possible directions. In actuality, this is not true.
5)
The Bohr model for the spectra of a H-atom

12th Standard CBSE Physics Unit 7 Dual Nature of Radiation and Matter Model Question Paper - by Sharma - Kochi Aug 03, 2019 - View & Download

1)
A particle is dropped from a height H.The de-Broglie wavelength of the particle as a function of height is proportional to
2)
Relativistic corrections become necessary when the expression for the kinetic energy \(\frac { 1 }{ 2 } m{ v }^{ 2 }\) becomes comparable with \(m{ c }^{ 2 }\) where m is the mass of the particle.At what de-Broglie wavelength will relativistic corrections become important for an electron?
3)
Two photons, each of energy 2.5eV are simultaneously incident on the metal surface.If the work function of the metal is 4.5eV, then from the surface of metal
4)
Silver has a work function of 4.7eV when ultraviolet light of wavelength 100 nm is incident upon it, a potential 0f 7.7 is required to stop the photoelectrons from reaching the collector plate.How much potential will be required to stop the photoelectrons when light of wavelength 200 nm is incident upon silver?
5)
The ratio between masses of two particles is 1:2 and ratio between their temperatures is also 1:2 The ratio between their de-Broglie wavelength

12th CBSE Physics Unit 6 Wave Optics Model Question Paper - by Sharma - Kochi Jul 31, 2019 - View & Download

1)
Consider sunlight incident on a slit of width \({ 10 }^{ 4 }\)A. The image seen through the slit shall darkness as observed through the polaroid
2)
For light diverging from a point source
3)
The ratio of the speed of an object to the speed of its real image of magnification m in the case of a convex mirror is
4)
The relation between focal length \(f\) and radius of curvature \(R\) of a spherical mirror is
5)
The correct mirror equation is

CBSE 12th Standard Physics Chapter 5 Electromagnetic Waves Important Question Paper - by Sharma - Kochi Jul 29, 2019 - View & Download

1)
One requires 11 \(eV\) of energy to dissociate a carbon monoxide molecule into carbon and oxygen atom. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lines in
2)
The ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is
3)
An EM wave of intensity I falls on a surface kept in vacuum and experts radiation pressure kept in vacuum and experts radiation pressure p on it. Which of the following are true?
4)
The velocity of light in vacuum can be changed by changing
5)
The waves used in Telecommunications are

12th CBSE Physics Unit 4 Electromagnetic Induction and Alternating Currents Important Question Paper - by Sharma - Kochi Jul 27, 2019 - View & Download

1)
In the relation \(\phi \) = BA cos \(\theta \), \(\theta \) is angle........
2)
SI unit of magnetic flux is
3)
A wire of length 2m moves with a speed of 5m/s perpendicular to a magnetic field of induction 0.1 Wb/m². The e.m.f. induced in the wire is
4)
Choose the quality whose SI unit is not ohm.
5)
Which of the following does not have the dimension of time?

12th Standard CBSE Physics Unit 3 Magnetic Effects of Current Important Question Paper - by Sharma - Kochi Jul 26, 2019 - View & Download

1)
The magnetic field at a perpendicular distance of 2 cm from an infinite straight current carrying conductor is 2X10^-6 T. The current in the wire is
2)
A positive charge is moving towards an observer. The direction of magnetic induction lines is
3)
If a copper wire carries a direct current, the magnetic field associated with the current will be
4)
Current carrying wire produces
5)
A circular coil of n turns and radius r carries a current I. The magnetic field at the centre is

12th CBSE Physics Unit 2 Current Electricity Important Question Paper - by Sharma - Kochi Jul 24, 2019 - View & Download

1)
Is electric current a vector or scalar quantity? Explain.
2)
If the electric current is passed through a nerve, the man is excited, why?
3)
A steady current is flowing in a cylindrical conductor. Is there any electric field within the conductor?
4)
How can you keep a constant current inside a conductor?
5)
How does the drift velocity of electrons in a metal conductor vary with the increase in temperature?

CBSE 12th Physics Unit 1 Electrostatics Important Question Paper - by Sharma - Kochi Jul 18, 2019 - View & Download

1)
At a particular point, electric field depends upon
2)
The SI unit of electric field intensity is
3)
Electric field due to a single charge is
4)
Electric dipole moment is
5)
Electric field intensity (E) due to an electric dipole varies with distance (r) of the point from the centre of dipole as:

12th Standard CBSE Physics Model Question Paper - by Mark Jan 03, 2019 - View & Download

1)
In polar molecules, the centres of positive and negative charges of molecule do not coincide. The statement is always
2)
In a permanent magnet at room temperature
3)
Charges of magnitude 2Q and -Q are located at points (a, 0, 0) and (4a, 0, 0). Find the ratio of the flux of electric field due to these charges, through concentric spheres of radii 2a and 8a centered at the origin.
4)
Is it possible that there is no potential difference between the plates of a cell? If yes, under what condition?
5)
If the distance between two parallel current carrying wires is doubled, what is the force between them?

12th Standard CBSE Physics Important HOTs Problems - by Bala Dec 29, 2018 - View & Download

1)
What should be charge on a sphere of radius 2cm so that when it is brought in contact with another sphere of radius 5cm carrying a charge of \(10\mu C\),there is no net transfer of charge between the spheres?
2)
Two capacitors of capacitance \(6\mu F\) and \(12\mu F\) are connected in series with a battery.The voltage across the \(6\mu F\)capacitor is 2V.Compute the total battery voltage.
3)
Four point charge 10^-8 C,\(−2×{{10}^{−8}}C\) and \(-4\times {{10}^{-8}}C\) and \(6\times {{10}^{-8}}C\) are placed at the four corners of a square of side \(2\sqrt { 2 }cm. \) Calculate the electric potential at the centre of square.
4)
A proton placed in a uniform electric field of magnitude 2000N/C moves between two points in the direction of electric field .If the distance between the points is 0.2m,find the value of(i)p.d between the points,(ii)work done.
5)
A point charge \(+10\mu \) is at a distance 5cm directly above the centre of square of side 10cm as shown in fig.What is the magnitude of the electric flux through the square?

CBSE Grade 12 Physics Revision Test - by Bala Dec 29, 2018 - View & Download

1)
A point charge q is placed at the origin. How does the electric field due to the charge vary with distance r from the origin?
2)
A proton is placed in a uniform electric field directed along the positive x-axis. In which direction will it tend to move?
3)
If the radius of the Gaussian surface enclosing a charge q is halved, how does the electric flux through the Gaussian surface change?
4)
Why should electrostatic field be zero inside a conductor?
5)
Is it correct to write the unit of electric dipole moment as mC?

Dual Nature of Radiation and Matter Important Questions From CBSE 12th Physics - by Bala Dec 14, 2018 - View & Download

1)
A particle is dropped from a height H.The de-Broglie wavelength of the particle as a function of height is proportional to
2)
An electron is moving with an initial velocity \(\frac { h }{ mv } ={ v }_{ 0 }\overset { \wedge }{ L } \) and is in a magnetic field \(\vec { B= } \quad { B }_{ 0 }\vec { j } \) Then its de-Broglie wavelength
3)
The de-Broglie wavelength of a photon is twice the de-Broglie wavelength of an electron.The speed of the electron is \({ v }_{ e }=\frac { c }{ 100 } \) Then
4)
Which of the following has minimum stopping potential?
5)
The threshold wavelength for a metal having work function \({ \phi }_{ 0 }\quad is\quad { \lambda }_{ 0 }\).What is the threshold wavelength for a metal whose work function is \({ \phi }_{ 0 }/2\)

12th CBSE Physics Atoms and Nuclei Important Questions - by Bala Dec 10, 2018 - View & Download

1)
Taking the Bohr radius as a₀=53pm, the radius of Li⁺⁺ ion its ground state, on the basis of Boh''s model, will be about
2)
For the ground state, the electron in the H-atom has an angular momentum =h, according to the simple Bohr model.Angular momentum is a vector and hence there will be infinitely many orbits with the vector pointing in all possible directions.In actuality, this is not true,
3)
Consider aiming a beam of free electrons towards free protons.When they scatter, an electron and a proton cannot combine to produce a H-atom,
4)
A set of atoms in an excited state decays.
5)
The series of hydrogen spectrum which lies in visible region is

12th CBSE Physics Electronic Devices Important Questions - by Bala Dec 01, 2018 - View & Download

1)
The conduction band in a solid is partially filled at 0 k.The solid sample is
2)
In a \(p\)-type semiconductor the acceptor level is situated 60m eV above the valence band.The maximum wavelength of light required to produce a hole will be [use \(hc=12400 eVA\)
3)
A semiconductor is cooled from \(T_{ 1 }K\quad to\quad T_{ 2 }k\)Its resistance will
4)
In the middle of the depletion layer of a review biased \(p-n \) junction,the
5)
Choose the correct relation between the transistor parameters \(\alpha \quad and\quad \beta \)

12th CBSE Physics Communication Systems Important Question Paper - by Bala Nov 30, 2018 - View & Download

1)
Frequencies in the UHF range normally propagate by means of:
2)
A basic communication system consists of

(a) transmitter

(b) information source

(c) user of information

(d) channel

(e) receiver

Choose the correct sequence in which these are arranged in a basic communication system:
3)
Out of the following, which is not an essential element of a communication system?
4)
A device that connects one computer to another across ordinary telephone lines is called
5)
The fraction of world's human population using the services of internet is

12th Standard Physics Model Revision Question Paper 1 - by Bala Nov 29, 2018 - View & Download

1)
What is the cause of charging?
2)
A hollow metal sphere of radius 5cm is charged such that potential on its surface is 10V. What is the potential at the centre of the sphere?
3)
The cause of charging is ......... of electrons from ..... to ............
4)
Two identical cells each of emf \(\epsilon\), having negligible internal resistance r, are connected in parallel with each other across an external resistance R. What is the current through this resistance.
5)
Why is potentiometer preferred over a voltmeter for determining the emf of a cell?

12th Standard CBSE Physics HOTs Question - by Bala Sep 15, 2018 - View & Download

1)
The magnetic field at a perpendicular distance of 2 cm from an infinite straight current carrying conductor is 2X10^-6 T. The current in the wire is
2)
A positive charge is moving towards an observer. The direction of magnetic induction lines is
3)
If a copper wire carries a direct current, the magnetic field associated with the current will be
4)
A magnetic needle lying parallel to a magnetic field requires W units of work to turn it through \({ 60 }^{ ° }.\) The torque required to keep the needle in this position will be
5)
The work done in turning a magnet of magnetic moment M by an angle of \({ 90 }^{ ° }\) from the magnetic meridian is n times the corresponding work done to turn it through an angle of \({ 60 }^{ ° },\) where n is

Class 12 CBSE Physics Term Test Model Question Paper - by Bala Sep 15, 2018 - View & Download

1)
One requires 11 \(eV\) of energy to dissociate a carbon monoxide molecule into carbon and oxygen atom. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lines in
2)
A linearly polarized electromagnetic wave given as \(E={ E }_{ 0 }\overset { \wedge }{ i } cos\quad (kz-wt)\) incident wall at \(z=a\) . Assuming that the material of the wall os optically inactive, the reflected wave will be given as
3)
Light with an energy flux of \(20\quad W/cm^{ 2 }\) falls on a non-reflecting surface at normal incidence. If the surface has an area of \(30 cm^{ 2 }\), the total momentum delivered (for complete absorption) during \(30\) minutes is:
4)
The electric field intensity produced by the radiations coming from 100 W bulb at a 3m distance is E. The electric field intensity produced by the radiations coming from 50w bulb at the same distance is:
5)
In an electromagnetic wave, the electric and magnetic fields are 100 V/m and 0.265 A/m. The maximum energy flow per second per unit area will be

Communication Systems - Important Questions Model Question Paper 1 In 12th Physics - by Bala Jul 31, 2018 - View & Download

1)
Which of the following frequencies will be suitable for beyond the horizon communication using sky waves.
2)
A message signal of frequency \({ \omega }_{ m }\) is superposed on a carrier wave of frequency \({ \omega }_{ c }\) to get an amplitude modulated wave (AM). The frequency of the AM wave will be
3)
Identify the mathematical expression for amplitude modulated wave:
4)
A repeater is a combination of
5)
A device that connects one computer to another across ordinary telephone lines is called

Electronic Devices - Important Questions Model Question Paper 1 In 12th Physics - by Bala Jul 31, 2018 - View & Download

1)
The conduction band in a solid is partially filled at 0 k.The solid sample is
2)
The forbidden energy band gap in conductors,semiconductors and insulators are \(E_{ G1 },E_{ G2 }\)and \(E_{ G3 }\)respectively The relation among them is
3)
A p-type semiconductor is obtained by doping silicon with
4)
Which type of semiconductor is obtained by mixing arsenic with silicon?
5)
In a common emitter configuration,a transistor \(\beta =50\)and input resistance \(1k\quad \Omega \) if te peak value of a.c.input is 0.01 V then the peak value of collector currents is

Atoms And Nuclei - Important Questions Model Question Paper 1 In 12th Physics - by Bala Jul 31, 2018 - View & Download

1)
Taking the Bohr radius as a₀=53pm, the radius of Li⁺⁺ ion its ground state, on the basis of Boh''s model, will be about
2)
O₂ molecule consists of two oxygen atoms.In the molecule, nuclear force between the nuclei of the two atoms
3)
The Bohr model for the spectre of a H-atom
4)
The Balmer series for the H-atom can be observed
5)
A set of atoms in an excited state decays.

Dual Nature Of Matter And Radiation - Important Questions Model Question Paper 1 In 12th Physics - by Bala Jul 31, 2018 - View & Download

1)
A particle is dropped from a height H.The de-Broglie wavelength of the particle as a function of height is proportional to
2)
An electron (mass \(m\)) with an initial velocity \(v={ v }_{ 0 }\vec { i } ({ v }_{ 0 }>0)\quad \) is an electric field \(v={ v }_{ 0 }\vec { i } ({ v }_{ 0 }>0)\quad \) its de-Broglie wave-length at time \(t\) is given by
3)
Relativistic corrections become necessary when the expression for the kinetic energy \(\frac { 1 }{ 2 } m{ v }^{ 2 }\) becomes comparable with \(m{ c }^{ 2 }\) where m is the mass of the particle.At what de-Broglie wavelength will relativistic corrections become important for an electron?
4)
Which of the following has minimum stopping potential?
5)
What is de-Broglie wavelength associated with electron moving under a potential difference of 10⁴ V.

Wave Optics - Important Questions Model Question Paper 1 In 12th Physics - by Bala Jul 30, 2018 - View & Download

1)
Consider sunlight incident on a slit of width \({ 10 }^{ 4 }\)A. The image seen through the slit shall darkness as observed through the polaroid
2)
For light diverging from a point source
3)
In a concave mirror, an object is placed at a distance \({ d }_{ 1 }\) from the focus and the real image is formed at a distance \({ d }_{ 2 }\) from the focus. then the focal length of the nirror is:
4)
Image of an object in a concave mirror is
5)
Light of wavelength \(6000\quad \overset { \circ }{ A } \) falls on a plane reflecting surface. The reflected wavelength is

Electromagnetic Waves - Important Questions Model Question Paper 1 In 12th Physics - by Bala Jul 30, 2018 - View & Download

1)
One requires 11 \(eV\) of energy to dissociate a carbon monoxide molecule into carbon and oxygen atom. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lines in
2)
The ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is
3)
If \({ \mu }_{ 0 }\) be the permeability and \({ k }_{ 0 }\) the dielectric constant of a medium. its refractive index in given by
4)
The kinetic energy of a photon of frequency v, rest mass.\({ m }_{ 0 }\) having mass m while moving with velocity v is
5)
The electric field associated with an e.m. wave in vacuum is given by
\(\overset { \rightarrow }{ E } =\hat { i } 40\quad cos(kz-6\times { 10 }^{ 8 }t)\)
where E,z, and t are in volt/m. metre and seconds respectively. The value of wave factor k is:

12th Physics Model Question Paper - by Bala Jul 30, 2018 - View & Download

1)
In the relation \(\phi \) = BA cos \(\theta \), \(\theta \) is angle........
2)
Amount of charge induced in a circuit of resistance R is given by
3)
When number of turns of a soleniod is doubled, its self inductance becomes k times, where k=
4)
Phase difference between voltage across L and C in series is
5)
Q factor of resonance is given by

Magnetic Effects Of Current - Important Questions Model Question Paper 1 In 12th Physics - by Bala Jul 30, 2018 - View & Download

1)
A positive charge is moving towards an observer. The direction of magnetic induction lines is
2)
A thin ring of radius R metre has charge q coulomb uniformly spread on it. The ring rotates about its axis with a constant frequency of f revolutions/s. The value of magnetic field induction in Wb/m² at the centre of the ring is
3)
A circular coil carrying current behaves as a
4)
A current carrying circular loop of radius R is placed in the x-y plane with centre at the origin. Half of the loop with x>0 is now bent so that it now lies in the y-z plane.
5)
An electron moving in a circular orbit of radius r makes n rotations per second. The magnetic field produced at the centre has magnitude

Current Electricity - Important Questions Model Question Paper 1 In 12th Physics - by Bala Jul 27, 2018 - View & Download

1)
Is electric current a vector or scalar quantity? Explain.
2)
If the electric current is passed through a nerve, the man is excited, why?
3)
The specific resistance of copper, silver and constantan are (\(1.78 \times 10^{-6}\Omega cm, \ 10^{-6}\Omega cm \ \ and \ \ 48 \times 10^{-6}\Omega cm\)) respectively. Which is the best conductor and why?
4)
What are Non-ohmic devices? Give examples.
5)
Name three materials whose resistivity decreases with rising in temperature.

Electrostatics - Important Questions Model Question Paper 1 In 12th Physics - by Bala Jul 27, 2018 - View & Download

1)
At a particular point, electric field depends upon
2)
Electric field due to a single charge is
3)
Electric dipole moment is
4)
At a given distance from the centre of electic dipole, field intensity on axial line is k times the field intensity on equatorial line, where K=
5)
Electrostatic potential V at a point, distant r from a charge q varies as