# CBSE Class 12 Physics Term 1 Sample Paper Set C

See below CBSE Class 12 Physics Term 1 Sample Paper Set C with solutions. We have provided CBSE Sample Papers for Class 12 Physics as per the latest paper pattern issued by CBSE for the current academic year. All sample papers provided by our Class 12 Physics teachers are with answers. You can see the sample paper given below and use them for more practice for Class 12 Physics examination.

## CBSE Sample Paper for Class 12 Physics Term 1 Set C

Section A

Question 1. Point charges +4q, -q and +4q are kept on the X-axis at points x = 0, x = a and x = 2a respectively:
a) all the charges are in unstable equilibrium
b) all the charges are in stable equilibrium
c) none of the charges is in equilibrium
d) only – q is in stable equilibrium

A

Question 2. To make a condenser of 16 μF, 1000 volts, how many condensers are needed which have written on them “8μF ,, 250 volts”?
a) 8
b) 32
c) 40
d) 2

B

Question 3. A current of 0.25 A flows in the main circuit. Now, the resistance R is disconnected and then connected across the 4 Ω resistance. Current in the circuit is:

a) 1/19 A
b) 2/9A
c) 1/2
d) 1A

D

Question 4. Hollow spherical conductor with a charge of 500 C is acted upon by a force 562.5 N. What is E at its surface?
a) Zero
b) 4.5× 10−4NC−1
c) 1.125 NC-1
d) 2.25× 106NC−1

C

Question 5. In a region, the potential is represented by V(x, y, z) = 6x – 8xy – 8y + 6yz, where V is N volts and x, y, z are in metres. The electric force experienced by a charge of 2 coulomb situated at point (1, 1, 1) is:
a) 24 N
b) 4 √35 N
c) 30 N
d) 6√5 N

B

Question 6. The internal resistance of a cell of emf 2 V is 0.1 . It is connected to a resistance of 3.9 .The voltage across the cell will be:
a) 1.9 V
b) 1.95 V
c) 0.5 V
d) 2 V

B

Question 7. When a dc motor operates at 200 V, its initial current is 5A, but when it runs at maximum speed, the current is only 3A. What is its back emf?
a) 80 V
b) Zero
c) 100 V
d) 120 V

A

Question 8. The value of 1 Bohr magneton is: [Given h = 6.62×10-34 Js, e = 1.6 × 10-19 C and me = 9.1 × 10-31 kg]
a) 7.27 × 10-24 Am2
b) 9.27 × 10-24 Am2
c) 10.57 × 10-24 Am2
d) 8.57 × 10-24 Am2

B

Question 9. The magnetic flux linked with a coil (in Wb) is given by the equation:
ϕ = 5 t2 + 3 t+ 16
The induced e.m.f. in the coil in the fourth second will be
a) 10 V
b) 145 V
c) 210 V
d) 108 V

A

Question 10. A hair dryer meant for 110V, 60Hz is to be used in India. If 220 V is the supply voltage in India, the turns ratio for a transformer would be
a) step-down transformer with turn ratio 3 : 1
b) step-up transformer with turn ratio 1 : 2
c) step-down transformer with turn ratio 2 : 1
d) step-down transformer with turn ratio 2.5 : 1

C

Question 11. To convert a galvanometer into an ammeter, we connect:
a) high resistance in parallel
b) low resistance in parallel
c) high resistance in series
d) low resistance in series

B

Question 12. A current is passed though two coils connected in series. The potential difference across the first coil of resistance 2 ohm is 5 volt. If the potential difference across the second coil is 12.5 volt, the resistance of the second coil is
a) 12.5 ohm
b) 4 ohm
c) 5 ohm
d) 7 ohm

C

Question 13. The working of a dynamo is based on the principle of
a) Chemical effect of current
b) Electromagnetic induction
c) Magnetic effect of current
d) Heating effect of current

B

Question 14. A series circuit consists of an ac source of variable frequency, a 115.0 Ω resistor, a 1.25 capacitor, and a 4.50-mH inductor. Impedance of this circuit when the angular frequency of the ac source is adjusted to twice the resonant angular frequency is
a) 146 Ω
b) 176 Ω
c) 166 Ω
d) 156 Ω

B

Question 15. If a charge q is placed at the centre of the line joining two equal charges Q such that the system is in equilibrium, then the value of q is :
a) − Q/2
b) Q/4
c) − Q/4
d) Q/2

C

Question 16. If the charge on a capacitor is increased by 2 coulomb, the energy stored in it increases by 21%. The original charge on the capacitor (in coulomb) is –
a) 30
b) 20
c) 40
d) 10

B

Question 17. In the following diagram which particle has the highest e/m value?

a) D
b) C
c) A
d) B

A

Question 18. If C and R denote capacitance and resistance, then dimensions of CR are
a) [M0LT0A1]
b) [MLT0A2]
c) [M0L0TA0]
d) [ML0TA-2]

C

Question 19. The susceptibility of a magnetic substance is found to depend on temperature and the strength of the magnetising field. The material is a:
a) diamagnet
b) superconductor
c) ferromagnet
d) paramagnet

D

Question 20. Capacitors are used in electrical circuits where appliances need more:
a) watt
b) resistance
c) voltage
d) current

D

Question 21. If a charge q is placed at the centre of the line joining two equal like charges Q such that the system is in equilibrium, then the value of q is:
a) −Q/2
b) Q/2
c) 4Q
d) −Q/4

D

Question 22. A current I = I0 sin (ωt + π/2) flows in a circuit across which an alternating potential E = E0 sin t is applied. The power consumed in the circuit is
a) E0 I0 / 2
b) E0 I0
c) E
d) zero

D

Question 23. Current in a circuit falls from 5 A to 0 A in 0.1 s. If an average emf of 200 V is induced, the self-inductance of the circuit is
a) 5H
b) 4H
c) 2H
d) 3H

B

Question 24. A magnet of magnetic moment M is suspended in a uniform magnetic field B. The maximum value of torque acting on the magnet is
a) zero
b) MB
c) 2MB
d) 1/2MB

B

Question 25. A galvanometer of resistance 25 Ω is shunted by a 2.25 Ωwire. The part of total current Io that flows through the galvanometer is given by

C

Section B

Question 26. A beam of cathode rays is subjected to crossed electric (E) and magnetic fields (B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by where V is the potential difference between cathode and anode.

A

Question 27. Four electric charges + q, + q, -q and – q are placed at the corners of a square of side 2 L (see figure). The electric potential at point A, midway between the two charges + q and + q is

D

Question 28. A conducting sphere of radius 10 cm is charged with 10 μC. Another uncharged sphere of radius 20 cm is allowed to touch it for some time. After that if the spheres are separated, then surface density of charges on the spheres will be in the ratio of
a) 1 : 1
b) 2 : 1
c) 1 : 3
d) 1 : 2

B

Question 29. A transformer has 500 primary turns and 10 secondary turns. If the secondary has a resistive load of 15 , the currents in the primary and secondary respectively, are
a) 3.2 × 10-3 A, 3 .2 × 10-3 A
b) 3.2 × 10-3 A, 0.16 A
c) 0.16 A, 3.2 × 10-3 A
d) 0.16 A, 0.16 A

B

Question 30. A wire loop is rotated in a magnetic field. The frequency of change of direction of the induced emf is:
a) four times per revolution
b) twice per revolution
c) six times per revolution
d) once per revolution

B

Question 31. In the magnetic meridian of a certain place, the horizontal component of the earth’s magnetic field is 0.26 G and the dip angle is 60o. What is the magnetic field of the earth at this location?
a) 0.52 G
b) 0.58 G
c) 0.65 G
d) 0.62 G

A

Question 32. A square loop of wire of each side 50 cm is kept so that its plane makes an angle with a uniform magnetic field of induction IT. The magnetic field is withdrawn in 0.1 s. It is found that the induced emf across the loop is 125 mV. The angle is:
a) 45o
b) 60o
c) 90o
d) 30o

A

Question 33. The mobility of charge carriers increases with:
a) increase in the average collision time
b) increase in the mass of the charge carriers
c) the decrease in the charge of the mobile carriers
d) increase in the electric field

A

Question 34. If the potential of a capacitor having capacity 8 pF is increased from 10 V to 20 V, then increase in its energy will be:
a) 12 × 10-4 J
b) 4 × 10-6 J
c) 12 × 10-6 J
d) 4 × 10-4 J

A

Question 35. An electric kettle boils some water in 16 min. Due to some defect, it becomes necessary to remove 10% turns of the heating coil of the kettle. Now, how much time will it take to boil the same amount of water?
a) 19.6 min
b) 14.4 min
c) 15.0 min
d) 12.7 min

B

Question 36. An inductor with L = 9.50 mH is connected across an ac source that has voltage amplitude 45.0 V. Frequency of the source that results in a current amplitude of 3.90 A is
a) 180 Hz
b) 129 Hz
c) 193 Hz
d) 150 Hz

C

Question 37. A coil of cross-sectional area 400 cm2 having 30 turns is making 1800 rev/min in a magnetic field of 1 T. The peak value of the induced emf is:
a) 2.26 V
b) 226 V
c) 0.6 V
d) 0.4 V

B

Question 38. A toroid wound with 60 turns/m of wire carries a current of 5.00 A. The torus is iron, which has a magnetic permeability of μm = 5000μ0 under the given conditions. H and B inside the iron are
a) 380A/m,1.98T
b) 340A/m,1.88T
c) 300A/m, 1.88T
d) 340A/m, 2.88T

C

Question 39. In an oscillating LC-circuit, the maximum charge on the capacitor is Q. The charge on the capacitor, when the energy is stored equally between the electric and magnetic field is:
a) Q/ √2
b) Q/2
c) Q
d) Q/√3

A

Question 40. The wire of the potentiometer has resistance 4 ohms and length 1 m. It is connected to a cell of e.m.f. 2 volts and internal resistance 1 ohm, the potential gradient in the potentiometer wire is
a) 1.6 volt/m
b) 2.0 volt/m
c) 1.2 volt/m
d) 0.8 volt/m

A

Question 41. A hot electric iron has a resistance of 80Ω and is used on a 200 V source. The electrical energy spent, if it is used for 2 h, will be:
a) 800 Wh
b) 1000 Wh
c) 2000 Wh
d) 8000 Wh

B

Question 42. A point charge +10μC is at a distance 5 cm directly above the centre of a square of side 10 cm, as shown in Figure. What is the magnitude of the electric flux through the square?
(Hint: Think of the square as one face of the cube with edge 10cm)

a) 3. 4× 105Nm2/C
b) 2. 55× 105Nm2/C
c) 1. 88× 105Nm2/C
d) 3. 0× 105Nm2/C

C

Question 43. A galvanometer having 30 divisions has a current sensitivity of 20μA/div. It has a resistance of 25 ohm. How will you convert it into an ammeter measuring upto 1 ampere.
Find the shunt to be used.
a) 0.30 Ω
b) 0.15 Ω
c) 0.015 Ω
d) 0.030 Ω

C

Question 44. Angle of dip is 90° at
a) both poles and equator
b) equator
c) poles
d) none of these

C

Question 45. Assertion (A): Electric field is discontinuous across the surface of a spherical charged shell.
Reason (R): Electric potential is continuous across the surface of a spherical charged shell.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.

B

Question 46. Assertion: A compass needle when placed on the magnetic north pole of the earth rotates in vertical direction.
Reason: The earth has only horizontal component of its magnetic field at the north pole.
a) Both A and R are true and R is the correct explanation of A
b) Both A and R are true but R is NOT the correct explanation of A
c) A is true but R is false
d) A is false and R is also false

D

Question 47. Assertion (A): An induced current has a direction such that the magnetic field due to the current opposes the change in the magnetic flux that induces the current.
Reason (R): Above statement is in accordance with the conservation of energy.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.

B

Question 48. Assertion (A): The alternating current lags behind the e.m.f. by a phase angle of π/2 , when ac flows through an inductor.
Reason (R): The inductive reactance increases as the frequency of ac source decreases.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.

C

Question 49. Assertion (A): A deuteron and an -particle are placed in an electric field. If F1 and F2 be the forces acting on them and a1 and a2 be their accelerations respectively then, a1 = a2.
Reason (R): Forces will be same in electric field.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.

C

Section C

Question 50. Dielectric polarization is the phenomenon, in which atomic dipoles are aligned
a) at an acute angle to the direction of the electric field
b) perpendicular to the direction of the electric field
c) in the direction of the electric field
d) opposite to the direction of the electric field

C

Question 51. Each of the two-point charges are doubled and their distance is halved. Force of interaction becomes n times, where n is
a) 1
b) 18
c) 16
d) 4

C

Question No. 52 to 55 are based on the given text. Read the text carefully and answer the questions:

According to Ohm’s law, the current flowing through a conductor is directly proportional to the potential difference across the ends of the conductor i.e., I∝V=V/I = R, where R is resistance of the conductor. Electrical resistance of a conductor is the obstruction posed by the conductor to the flow of electric current through it. It depends upon length, area of cross-section, nature of material and temperature of the conductor. We can write, R ∝ l/A or R =ρ l/A where ρ is electrical resistivity of the material of the conductor.

Question 52. Dimensions of electric resistance is
a) [M-1L-2 T-1A]
b) [[M-1L2T2A-1]
c) [ML2T-2A-2]
d) [ML2T-3A-2]

D

Question 53. If 1 A current flows through a conductor when potential difference of 2 volt is applied across its ends, then the resistance of the conductor is
a) 5 × 107 Ω
b) 1.5 × 105 Ω
c) 2 × 106 Ω
d) 3 × 105 Ω

C

Question 54. Specific resistance of a wire depends upon
a) mass
b) none of these
c) cross-sectional area
d) length