# Class 12 Physics Sample Paper Term 1 Set B

Please see below Class 12 Physics Sample Paper Term 1 Set B with solutions. We have provided Class 12 Physics Sample Papers with solutions designed by Physics teachers for Class 12 based on the latest examination pattern issued by CBSE. We have provided the following sample paper for Term 1 Class 12 Physics with answers. You will be able to understand the type of questions which can come in the upcoming exams.

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

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. Suppose the charge of a proton and an electron differ slightly. One of them is – e, the other is (e+e).
If the net f electrostatic force and gravitational force between two hydrogen atoms placed at a distance d (much greater than atomic size) apart is zero, then Δe is of the order of : [Given mass of hydrogen mH = 1.67 × 10-27 kg]
(A) 10–23 C
(B) 10–37 C
(C) 10–47 C
(D) 10–20 C

B

Q.2. The electrostatic potential on the surface of a charged conducting sphere is 100 V.
Two statements are made in this regard :
S1 : At any point inside the sphere, electric intensity is zero.
S2 : At any point inside the sphere, the electrostatic potential is 100 V.
Which of the following is a correct statement?
(A) S1 is true, but S2 is false.
(B) Both S1 and S2 are false.
(C) S1 is true, S2 is also true and S1 is the cause of S2.
(D) S1 is true, S2 is also true but the statements are independent.

C

Q. 3. Equipotential at a great distance from a collection of charges whose total sum is not zero are approximately
(A) spheres.
(B) planes.
(C) paraboloids.
(D) ellipsoids.

A

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

D

Q. 5. Which of the following characteristics of electrons determines the current in a conductor?
(A) Drift velocity alone
(B) Thermal velocity alone
(C) Both drift velocity and thermal velocity
(D) Neither drift nor thermal velocity.

A

Q. 6. A metal rod of length 10 cm and a rectangular cross-section of 1 cm × 1/2cm is connected to a battery across opposite faces. The resistance will be
(A) maximum when the battery is connected across 1 cm × 1/2 cm faces.
(B) maximum when the battery is connected across 10 cm × 1 cm faces.
(C) maximum when the battery is connected across 10 cm × 1/2 cm faces.
(D) same irrespective of the three faces.

A

Q. 7. Two positive ions, each carrying a charge q, are separated by a distance d. If F is the force of repulsion between the ions, the number of electrons missing from each ion will be (e being the charge on an electron) :

C

Q. 8. A thin conducting ring of radius R is given a charge +Q. The electric field at the centre O of the ring due to the charge on the part AKB of the ring is E. The electric field at the centre due to the charge on the part ACDB of the ring is :

(A) 3 E along OK
(B) 3 E along KO
(C) E along OK
(D) E along KO

C

Q. 9. Which of the following I-V characteristic represent the characteristic of a Ohmic conductor?

D

Q. 10. What is the potential difference between points A and B in the following circuit?

(A) 10 V
(B) 5 V
(C) 2.5 V
(D) 20 V

B

Q. 11. The acceleration of an electron in an electric field of magnitude 50 V/cm, if e/m value of the electron is 1.76 × 1011 C/kg, is :
(A) 8.8×1014 m/sec2
(B) 6.2×1013 m/sec2
(C) 5.4×1012 m/sec2
(D) Zero

A

Q. 12. A toroid of n turns, mean radius R and cross-sectional radius a carries current I. It is placed on a horizontal table taken as x-y plane. Its magnetic moment m
(A) is non-zero and points in the z-direction by symmetry.
(B) points along the axis of the toroid (m = mφ).
(C) is zero, otherwise there would be a field falling as 1/r3 at large distances outside the toroid.

C

Q. 13. A square of side L meters lies in the x-y plane in a region where the magnetic field is given by  B = Bo (2ˆi + 3ˆj + 4kˆ) Tesla, where B0 is constant. The magnitude of flux passing through the square is
(A) 2BoL2Wb
(B) 3BoL2Wb
(C) 4BoL2Wb
(D) √229B0L2Wb

C

Q. 14. A loop, made of straight edges has six corners at A(0, 0, 0), B(L, 0, 0) C(L, L, 0), D(0, L, 0), E(0, L, L) and F(0, 0, L). A magnetic field B=B0 (iˆ + kˆ) Tesla is present in the region. The flux passing through the loop ABCDEFA (in that order) is
(A) BoL2 Wb.
(B) 2BoL2 Wb.
(C) √2BoL2 Wb .
(D) 4BoL2Wb.

B

Q. 15. A capacitor of 20 μF is charged to 500 volts and connected in parallel with another capacitor of 10 μF and charged to 200 volts. The common potential is :
(A) 200 volts
(B) 300 volts
(C) 400 volts
(D) 500 volts

C

Q. 16. The capacity of a parallel plate condenser is 5 μF. When a glass plate is placed between the plates of the conductor, its potential becomes 1/8th of the original value. The value of dielectric constant will be :
(A) 1.6
(B) 5
(C) 8
(D) 40

C

Q. 17. A condenser of capacity 50 μF is charged to 10 volts. Its energy is equal to :
(A) 2.5×10−3 joule
(B) 2.5×10−4 joule
(C) 5×10−2 joule
(D) 1.2×10−8 joule

A

Q. 18. An alternating current generator has an internal resistance Rg and an internal reactance Xg. It is used to supply power to a passive load consisting of a resistance Rg and a reactance XL. For maximum power to be delivered from the generator to the load, the value of XL is equal to
(A) zero
(B) Xg
(C) −Xg
(D) Rg

C

Q. 19. When a voltage measuring device is connected to AC mains, the meter shows the steady input voltage of 220 V. this means
(A) input voltage cannot be AC voltage, but a DC voltage.
(B) maximum input voltage is 220 V.
(C) The meter reads not v but (v2) and is calibrated to read √(v2 ).
(D) The pointer of the meter is stuck by some mechanical defect.

C

Q. 20. In a charged capacitor, the energy resides :
(A) the positive charges.
(B) both the positive and negative charges
(C) the field between the plates.
(D) around the edge of the capacitor plates.

C

Q. 21. Electric field inside a hollow conducting sphere is
(A) zero
(B) infinite
(C) depends on the magnitude of charge
(D) depends on the radius of the sphere

A

Q. 22. Fuse wire has high resistance and low melting point.
(A) should have high resistance
(B) should have low melting point
(C) should have low resistance
(D) both (A) and (B)

D

Q. 23. The resistance of superconductor is
(A) too large
(B) too small
(C) Negative
(D) zero

D

Q. 24. An electron and a proton moving with same velocity enters a magnetic field.
(A) Proton will experience more force
(B) Electron will experience more force
(C) Both will experience same force
(D) Force is mass dependent

C

Q. 25. Faraday’s laws of electromagnetic induction are consequences of law of conservation of
(A) Energy
(B) Momentum
(C) Mass
(D) None of the above

A

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. The average value of current over a complete cycle is
(A) 0
(B) I0
(C) I0/2
(D) I0/√2

A

Q. 27. Which one of the following has dimension of time?
(A) LR
(B) LC
(C) 1/RC
(D) RC

D

Q. 28. In a LCR circuit energy is dissipated by
(A) L
(B) C
(C) R
(D) All of the above

C

Q. 29. The ratio of XC and XL in a A.C. circuit is
(A) 1
(B) 1/ω2LC
(C) ω2L
(D) None of the above

B

Q. 30. In series resonant circuit, the total reactance is
(A) 0
(B) ∞
(C) Maximum
(D) Minimum

A

Q. 31. A metal plate can be heated by
(A) placing in a time varying magnetic field.
(B) passing either a direct or alternating current.
(C) placing in a space varying magnetic field, but does not vary with time.
(D) both (A) and (B) are correct.

D

Q. 32. Which of the following is not an application of eddy current?
(A) Electric power meters
(B) Induction furnace
(C) Magnetic brakes in trains
(D) LED lights

D

Q. 33. 1 Henry is equal to
(A) Weber / Volt
(B) Weber / ampere
(C) Weber Ampere
(D) Weber Volt

B

Q. 34. 1 Farad is equivalent to
(A) 1 C/J
(B) 1 J/C
(C) 1 C2/J
(D) 1 C2/J2

C

Q. 35. The role of inductance is equivalent to
(A) Force
(B) Inertia
(C) Moment
(D) Energy

B

Q. 36. Which of the following represents Ampere’s Circuital law?

B

Q. 37. The nature of parallel and anti-parallel current carrying wires are
(A) parallel current carrying wires repel and anti-parallel current carrying wires attract.
(B) parallel current carrying wires attract and anti-parallel currents carrying wires repel.
(C) both attract.
(D) both repel.

B

Q. 38. The defection of pointer of a moving coil galvanometer is given by

B

Q. 39. A moving coil galvanometer can be converted into an ammeter by
(A) putting a shunt in series.
(B) putting a shunt in parallel.
(C) putting a high value resistance in series.
(D) Putting a high value resistance in parallel.

B

Q. 40. The conversion of a moving coil galvanometer into a voltmeter is done by
(A) putting a shunt in series.
(B) putting a shunt in parallel.
(C) putting a high value resistance in series.
(D) Putting a high value resistance in parallel.

C

Q. 41. Two thin long parallel wires carrying current I ampere is separated by a distance r. The magnitude of the force per unit length applied by one wire on the other is
(A) μ0I2 / 2πr
(B) μ0I2 / r2
(C) μ0I2 / 4πr
(D) μ0I2 / 2πr2

A

Q. 42. The force on a current carrying conductor in a magnetic field is maximum, when angle between the length of the conductor and the magnetic field is:
(A) π/4
(B) π/2
(C) π
(D) 0

B

Q. 43. You are given three voltmeters A, B and C having internal resistance 50 Ω, 50 kΩ and 1 MΩ. Which one will you select for better accuracy?
(A) A
(B) B
(C) C
(D) Any one

C

Q. 44. A current carrying coil is placed in a uniform magnetic field. If θ is the angle between the axis of the coil and the direction of magnetic field, then the torque is directly proportional to:
(A) sin θ
(B) cos θ
(C) cosec θ
(D) sec θ

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.

A

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

A

Q.46. Assertion (A) : Electric field is always normal to equipotential surfaces and along the direction of decreasing order of potential.
Reason (R) : Negative gradient of electric potential is electric field.

A

Q. 47. Assertion (A) : Electric appliance with metal body has three electrical connections. But an electrical bulb has two electrical connection.
Reason (R) : Three pin connection reduces chances of electrical shocks.

A

Q. 48. Assertion (A) : The magnetic field at the ends of a very long current carrying solenoid is half of that at the centre.
Reason (R) : Magnetic field within a sufficiently long solenoid is uniform.

B

Q.49. Assertion (A) : The magnetic field configuration with 3 poles is not possible.
Reason (R) : No torque acts on a bar magnet itself due to its own field.

B

Section – C

This section consists of 6 multiple choice questions with an overall choice to attempt any 5. In case more than desirable number of questions are attempted, ONLY first 5 will be considered for evaluation.

Q. 50. The angle of dip where the horizontal component of earth’s magnetic field is equal to the vertical component is
(A) 30°
(B) 60°
(C) 45°
(D) 90°

C

Q. 51. The magnetic lines of force inside a bar magnet is
(A) South to North pole
(B) North to South pole
(C) There is no lines of force inside a bar magnet
(D) Direction of lines of force depends on the pole strength

A

CASE STUDY

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

Magnetic effects are generally smaller than electric effects. As a consequence, the force between currents is rather small, because of the smallness of the factor μ. Hence, it is difficult to demonstrate attraction or repulsion between currents. Thus, for 5 A current in each wire at a separation of 1 cm, the force per metre would be 5 × 10–4 N, which is about 50 mg weight. It would be like pulling a wire by a string going over a pulley to which a 50 mg weight is attached. The displacement of the wire would be quite unnoticeable. With the use of a soft spring, we can increase the effective length of the parallel current and by using mercury, we can make the displacement of even a few mm observable very dramatically. You will also need a constant-current supply giving a constant current of about 5 A. Take a soft spring whose natural period of oscillations is about 0.5–1 s. Hang it vertically and attach a pointed tip to its lower end, as shown in the figure here. Take some mercury in a dish and adjust the spring such that the tip is just above the mercury surface. Take the DC current source, connect one of its terminals to the upper end of the spring and dip the other terminal in mercury. If the tip of the spring touches mercury, the circuit is completed through mercury. Let the DC source be put off to begin with. Let the tip be adjusted so that it just touches the mercury surface. Switch on the constant current supply and watch the fascinating outcome. The spring shrinks with a jerk, the tip comes out of mercury (just by a mm or so), the circuit is broken, the current stops, the spring relaxes and tries to come back to its original position, the tip again touches mercury establishing a current in the circuit and the cycle continues with tick, tick, tick,…

Q. 52. Magnetic effects:
(A) are equal to electric effects.
(B) are greater than electric effects.
(C) are smaller than electric effects.
(D) cannot be compared with electric effects.

C

Q. 53. The force 10–3 N,is equivalent to:
(A) 100 mg
(B) 100 g
(C) 10 g
(D) 10 mg

A

Q. 54. Why the spring shrinks in Roget’s spiral ?
(A) The spring functions as a solenoid
(B) Due to force acting between two current carrying wires
(C) Due to magnetic effect of current
(D) Since the spring is soft

B

Q. 55. What are the main 3 components in a Roget’s spiral?
(A) Mercury, AC voltage source
(B) Mercury, DC voltage source
(C) Mercury, DC voltage source, key
(D) Mercury, AC voltage source, key