# Class 12 Physics Sample Paper Term 1 with Solutions Set C

Please refer to Class 12 Physics Sample Paper Term 1 With Solutions Set C provided below. The Sample Papers for Class 12 Physics have been prepared based on the latest pattern issued by CBSE. Students should practice these guess papers for class 12 Physics to gain more practice and get better marks in examinations. The Term 1 Sample Papers for Physics Standard 12 will help you to understand the type of questions which can be asked in upcoming examinations.

## Term 1 Sample Paper for Class 12 Physics With Solutions Set C

Section – A

This section consists of 25 multiple choice questions with overall choice to attempt any 20 questions. In case more than desirable number of questions are attempted, ONLY first 20 will be considered for evaluation.

Q. 1. A gold leaf electroscope
(A) measures the magnitude of positive charge present in a body.
(B) measures the magnitude of negative charge present in a body.
(C) Both (A) and (B)
(D) detects the presence of charge in a body.

D

Q. 2. The value of permittivity of free space is
(A) 8.854 × 1012 C2 N–1m–2
(B) 8.854 × 10-12 C2 N–1m–2
(C) 88.54 × 1012 C2 N–1m–2
(D) 88.54 × 10-12 C2 N–1m–2

B

Q. 3. Coulomb’s law agrees with the _______ law.
(B) Newton’s
(C) Lenz’s
(D) Maxwell

B

Q. 4. All of electrostatics is basically a consequence of _______ law and the superposition principle.
(A) Coulomb’s
(C) Kirchhoff’s
(D) Gauss’s

A

Q. 5. Electric field due to a charge Q at a point in space may be defined as the _______ that a unit _______ charge would experience if placed at that point.
(A) Force, negative
(B) Force, positive
(C) Torque, negative
(D) Torque, positive

B

Q. 6. For a positive charge, the electric field will be directed radially _______ from the charge and for negative charge the electric field is directed radially _______.
(A) Outward, outward
(B) Inward, inward
(C) Outward, inward
(D) Inward, outward

C

Q. 7. Which of the followings is a non-polar molecule?
(A) CO2
(B) H2O
(C) NH3
(D) SO2

A

Q. 8. A dielectric develops a net dipole moment in the presence of an external field. The dipole moment per unit volume is called polarisation and is denoted by P. For linear isotropic dielectrics, the expression of P is

A

Q. 9. Dielectric strength is
(A) the maximum electric field that a dielectric medium can withstand without break-down.
(B) the maximum magnetic field that a dielectric medium can withstand without break-down.
(C) the maximum electric current a dielectric medium can withstand without break-down.
(D) the maximum electric potential that a dielectric medium can withstand without break-down.

A

Q. 10. 1 million electrons from point A to B in 2 μs. The direction and magnitude of current are
(A) 8 × 10–7 A
(B) 8 × 107 A
(C) 0.8 × 107 A
(D) 0.8 × 10-7 A

D

Q. 11. In a Hydrogen atom, an electron moves in a orbit of radius 5 × 10–11 m with a speed π × 106 m/s. The equivalent current is
(A) 1.6 × 10–3 A
(B) 1.6 × 103 A
(C) 16 × 10-3 A
(D) 16 × 103 A

A

Q. 12. 1019 electrons per second move from A to B. 1019 protons per second move from B to A. The magnitude and the direction of current are
(A) 3.2 A, B to A
(B) 3.2 A, A to B
(C) 32 A, B to A
(D) 32 A, A to B

A

Q. 13. For a straight current carrying wire which of the following graph is incorrect?

C

Q. 14. A circular loop of one turn carries a current I. The wire of the loop is used to construct a loop of two turns and the same current I is allowed to flow through it. The field at the center of this coil will be times of the first coil.
(A) 2
(B) 4
(C) 3
(D) 8

A

Q. 15. Which one of the following statements is correct?
(A) Ammeter and voltmeter have the resistance of same order.
(B) Voltmeter is a high resistance galvanometer and an ammeter is a low resistance galvanometer
(C) Ammeter is a high resistance galvanometer and voltmeter is a low resistance galvanometer
(D) Ammeter is used in parallel and voltmeter is used in series in a circuit.

B

Q. 16. An alpha-particle is moving in a magnetic field (5i 10j ) + T with a velocity 5 × 103 ˆi ms–1. The magnetic force acting on the particle is
(A) 16 × 10–16 ˆk dyne
(B) 16 × 1016 ˆk dyne
(C) 16 × 10–16 ˆk N
(D) 16 × 1016 ˆk N

C

Q. 17. Two capacitors 2 μF and 3 μF are connected in series with a 10 V battery. When the capacitors get charged fully then
(A) The potential difference across the 2 μF and 3 μF capacitors are respectively 4 V and 6 V
(B) The potential difference across the 2 μF and 3 μF capacitors are respectively 6 V and 4 V
(C) The ratio of charges on the two capacitors is 1:1
(D) The ratio of electrical energies stored is 1:1

B

Q. 18. Two copper wires of length l and 2l have radii 2r and r respectively. The ratio of the specific resistances is
(A) 1:1
(B) 1:2
(C) 2:1
(D) 1:3

A

Q. 19. The magnetic dipole moment of a current loop is independent of
(A) current in the loop.
(B) area of the loop.
(C) number of turns on the loop.
(D) magnetic field in which it is lying.

D

Q. 20. An electron is moving in a circular orbit of radius 0.5 nm with a frequency 5 × 1019 Hz in anticlockwise direction. The loop current is
(A) 8 A, anti-clockwise
(B) 8 A, clockwise
(C) 5 A, anti-clockwise
(D) 5 A, clockwise

B

Q. 21. A charged 30μF capacitor is connected to a 3 mH inductor. The angular frequency of free oscillation is
(A) 10000 × 3 rad/s
(C) 10000/3 Hz
(D) None of the above

B

Q. 22. The inductance between A and B is

(A) L
(B) 3L
(C) L/3
(D) 3/L

C

Q. 23. Transformer works on the principle of
(A) Magnetic effect of electric current
(B) Mutual induction
(C) Self induction
(D) Electrical inertia

B

Q. 24. Consider the following two statements:
Statement I: Kirchhoff’s junction law follows conservation of charge.
Statement II: Kirchhoff’s loop law follows conservation of energy.
Which of the followings is true?
(A) Both statements I and II are wrong
(B) Both statements I and II are correct.
(C) Statement I is correct. Statement II is wrong
(D) Statement II is correct. Statement I is wrong.

B

Q. 25. The potential difference between the points X and Y is

(A) 3V
(B) 6V
(C) 9V
(D) –9V

C

Section – B

This section consists of 24 multiple choice questions with overall choice to attempt any 20 questions. In case more than desirable number of questions are attempted, ONLY first 20 will be considered for evaluation.

Q. 26. A hollow insulated conducting sphere is given a positive charge of 10 μC. What will be the electric field at the centre of the sphere if its radius is 2 meters :
(A) Zero
(B) 5 μCm−2
(C) 20 μCm−2
(D) 8 μCm−2

A

Q. 27. Figure shows the electric lines of force emerging from a charged body. If the electric field at A and B are EA and EB respectively and if the displacement between A and B is r then :

(A) EA>EB
(B) EA<EB
(C) EA=EB/r
(D) EA=EB/r2

A

Q. 28. The electric potential at a point on the axis of an electric dipole depends on the distance r of the point from the dipole as :
(A) ∝ 1/r
(B) ∝ 1/r2
(C) ∝ r
(D) ∝ 1/r3

B

Q. 29. An electric dipole when placed in a uniform electric field E will have minimum potential energy, if the positive direction of dipole moment makes the following angle with E :
(A) π
(B) π/2
(C) Zero
(D) 3π/2

C

Q. 30. The electrostatic force between the metal plates of an isolated parallel plate capacitor C having a charge Q and area A, is :
(A) proportional to the square root of the distance between the plates.
(B) linearly proportional to the distance between the plates.
(C) independent of the distance between the plates.
(D) inversely proportional to the distance between the plates.

C

Q. 31. The capacity of a parallel plate condenser is 10 μF, when the distance between its plates is 8 cm. If the distance between the plates is reduced to 4 cm, then the capacity of this parallel plate condenser will be :
(A) 5 μF
(B) 10 μF
(C) 20 μF
(D) 40 μF

C

Q. 32. In the figure, three capacitors each of capacitance 6 pF are connected in series. The total capacitance of the combination will be :

(A) 9×10−12 F
(B) 6×10−12 F
(C) 3×10−12 F
(D) 2×10−12 F

D

Q. 33. Three capacitors of capacitance 3 μF, 10 μF and 15 μF are connected in series to a voltage source of 100 V. The charge on 15 μF is :
(A) 50 μC
(B) 100 μC
(C) 200 μC
(D) 280 μC

C

Q. 34. The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is :
(A) 1.0 Ω
(B) 0.2 Ω
(C) 0.5 Ω
(D) 0.8 Ω

C

Q. 35. The temperature co-efficient of resistance of a wire is 0.00125/oC. At 300 K it’s resistance is 1 Ω. The resistance of the wire will be 2 Ω at :
(A) 1154 K
(B) 1127 K
(C) 1100 K
(D) 1400 K

C

Q. 36. By ammeter, which of the following can be measured :
(A) electric potential.
(B) potential difference.
(C) current.
(D) resistance.

C

Q. 37. In the electric field of a point charge q, a certain charge is carried from point A to B, C, D and E. Then the work done :

(A) Is least along the path AB
(B) Is least along the path AD
(C) Is zero along all the paths AB, AC, AD and AE
(D) Is least along

C

Q. 38. A coil of self-inductance L is connected in series with a bulb B and an AC source. Brightness of the bulb decreases when :
(A) an iron rod is inserted in the coil.
(B) frequency of the AC source is decreased.
(C) number of turns in the coil is reduced.
(D) A capacitance of reactance XC = XL is included in the same circuit.

A

Q. 39. An e.m.f. of 5 volt is produced by a self inductance, when the current changes at a steady rate from 3 A to 2 A in 1 millisecond. The value of self inductance is :
(A) Zero
(B) 5 H
(C) 5000 H
(D) 5 mH

D

Q. 40. When the number of turns and the length of the solenoid are doubled keeping the area of crosssection same, the inductance :
(A) Remains the same
(B) Is halved
(C) Is doubled
(D) Becomes four times

C

Q. 41. The self-inductance of a coil is 5 henry, a current of 1 amp change to 2 amp within 5 second through the coil. The value of induced e.m.f. will be :
(A) 10 volt
(B) 0.10 volt
(C) 1.0 volt
(D) 100 volt

C

Q. 42. The quality factor of LCR circuit having resistance (R) and inductance (L) at resonance frequency (ω) is given by :
(A) ωL/R
(B) R/ωL
(C) (ωL/R)1/2
(D) (ωL/R)2

A

Q. 43. For high frequency, a capacitor offers :
(A) More reactance
(B) Less reactance
(C) Zero reactance
(D) Infinite reactance

B

Q. 44. The phase difference between the current and voltage of LCR circuit in series combination at resonance is :
(A) 0°
(B) π/2
(C) π
(D) – π

A

Given below are two statements labelled as Assertion (A) and Reason (R)

Directions: In the following questions, a statement of Assertion (A) and is followed by a statement of

Reason (R). Mark the correct choice as:
(A) Both Assertion (A) and Reason (R) are true, and Reason(R) is the correct explanation of (A).
(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
(C) Assertion (A) is true, but Reason (R) is false.
(D) Assertion (A) is false, but Reason (R) is true.

Q. 45. Assertion (A): In a non-uniform electric field, a dipole will have translatory as well as rotatory motion.
Reason (R): In a non-uniform electric field, a dipole experiences a force as well as torque.

A

Q. 46. Assertion (A): An alternator is a machine which converts mechanical energy into electrical energy.
Reason (R): When a coil rotates in a magnetic field an e.m.f. is induced in it.

A

Q. 47. Assertion (A): Fuse wire has high resistance and low melting point.
Reason (R): Fuse wire is for small current flow only.

C

Q. 48. Assertion (A): Magnetic field interacts with a moving charge only.
Reason (R): Moving charge produces a magnetic field.

A

Q. 49. Assertion(A): Faraday’s laws of electromagnetic induction are consequences of law of conservation of energy.
Reason (R): The parameter LR in a L-R circuit has the dimension of time.

C

Section – C

Read the following text and answer the questions

Q. 50. The electric potential at a point (x, y, z) is given by
V = – xy2 – xz3 + 4
The electric field E at that point is

A

Q. 51. A potentiometer wire has length of 4 m and resistance 8Ω. The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2V, so as to get a potential gradient 1 mV per cm of the wire is
(A) 32Ω
(B) 40Ω
(C) 44Ω
(D) 48Ω

A

CASE STUDY

Read the following text and answer the following questions on the basis of the same:

Tuning a radio set: In essence the simplest tuned radio frequency receiver is a simple crystal set. Desired frequency is tuned by a tuned coil / capacitor combination, and then the signal is presented to a simple crystal or diode detector where the amplitude modulated signal, is demodulated. This is then passed straight to the headphones or speaker. In radio set there is an LC oscillator comprising of a variable capacitor (or sometimes a variable coupling coil), with a knob on the front panel to tune the receiver.
Capacitor used in old radio sets is gang capacitor. It consists of two sets of parallel circular plates one of which can rotate manually by means of a knob. The rotation causes overlapping areas of plates to change, thus changing its capacitance. Air gap between plates acts as dielectric.
The capacitor has to be tuned in tandem corresponding to the frequency of a station so that the LC combination of the radio set resonates at the frequency of the desired station.

When capacitive reactance (XC) is equal to the inductive reactance (XL), then the resonance occurs and the resonant frequency is given by ω0 = 1/√LC current amplitude becomes maximum at the resonant frequency. It is important to note that resonance phenomenon is exhibited by a circuit only if both L and C are present in the circuit. Only then do the voltages across L and C cancel each other (both being out of phase) and the Current amplitude is Vm/R , the total source voltage appearing across R.
This means that we cannot have resonance in a RL or RC circuit.

Q. 52. Name the phenomenon involved in tuning a radio set to a particular radio station.
(A) Stabilization
(B) Rectification
(C) Resonance
(D) Reflection

C

Q. 53. Resonance may occur in:
(A) RL circuit.
(B) RC circuit.
(C) LC circuit.
(D) circuit having resistor only.

C

Q. 54. Resonance frequency is equal to:
(A) 1/LC
(B) 1/√ LC
(C) √L/C
(D) √C/L