# Electromagnetic Induction MCQ Type Questions for ISC Physics Class-12

Electromagnetic Induction MCQ Type Questions for ISC Physics Class-12 . These MCQ  / Objective Type Questions is based on latest reduced syllabus according 2021-22 session on bifurcated pattern. Main motto of MCQ Type Question is cracking the next upcoming exam of council. Visit official website CISCE for detail information about ISC Board Class-12 Physics.

## MCQ Type Questions for ISC Physics Class-12 Electromagnetic Induction

 Board ISC Class 12th (XII) Subject Physics Ch-Name Electromagnetic Induction Syllabus on bifurcated syllabus (after reduction) Session 2021-22 Topic MCQ / Objective Type Question

### MCQ Type Questions for ISC Physics Class-12

Question 1:  A wire loop is rotated in a magnetic field. The frequency of change of direction of the induced e.m.f. is

(a) four times per revolution
(b) six times per revolution
(c) once per revolution
(d) twice per revolution

Question 2:  In a region of magnetic induction B = 10–2 tesla, a circular coil of radius 30 cm and resistance p2 ohm is rotated about an axis which is perpendicular to the direction of B and which forms a diameter of the coil. If the coil rotates at 200 rpm the amplitude of the alternating current induced in the coil is

(a) 4p2 mA
(b) 30 mA
(c) 6 mA
(d) 200 mA

Question 3:  If the number of turns per unit length of a coil of solenoid is doubled, the self-inductance of the solenoid will
(a) remain unchanged
(b) be halved
(c) be doubled
(d) become four times

Question 4:   A 100 millihenry coil carries a current of 1A. Energy stored in its magnetic field is
(a) 0.5 J
(b) 1 J
(c) 0.05 J
(d) 0.1 J

Question 5:  The north pole of a long bar magnet was pushed slowly into a short solenoid connected to a short galvanometer. The magnet was held stationary for a few seconds with the north pole in the middle of the solenoid and then withdrawn rapidly. The maximum deflection of the galvanometer was observed when the magnet was

(a) moving towards the solenoid
(b) moving into the solenoid
(c) at rest inside the solenoid
(d) moving out of the solenoid

Answer: (d) moving out of the solenoid

Question 6:   Faraday’s laws are consequence of the conservation of

(a) charge
(b) energy
(c) magnetic field
(d) both (b) and (c)

Question 7:    Two identical coaxial coils P and Q carrying equal amount of current in the same direction are brought nearer. The current in

(a) P increases while in Q decreases
(b) Q increases while in P decreases
(c) both P and Q increases
(d) both P and Q decreases

Answer: (d) both P and Q decreases

Question 8:   Two coils are placed closed to each other. The mutual inductance of the pair of coils depends upon

(a) the rate at which currents are changing in the two coils.

(b) relative position and orientation of two coils.

(c) the material of the wires of the coils.

(d) the currents in the two coils.

Answer: (b) relative position and orientation of two coils.

Question 9:    When current in a coil changes from 5 A to 2 A in 0.1 s, average voltage of 50 V is produced. The self-inductance of the coil is

(a) 1.67 H

(b) 6 H

(c) 3 H

(d) 0.67 H

Question 10:   Whenever the magnetic flux linked with an electric circuit changes, an emf is induced in the circuit. This is called

(a) electromagnetic induction
(b) lenz’s law
(c) hysteresis loss
(d) kirchhoff’s laws

Question 11:  A horizontal conducting rod 10 m long extending from east to west is falling with speed 5 ms-1 at right angles to horizontal component of the earth’s magnetic field 0.3 x 10-4 wbm-2. Find the instantaneous value of emf induced in the coil.

(a) 15 x 10-3 V

(b) 1.5 x 10-3 V

(c)  0.3 x 10-4 V

(d) None of these

Answer: (b) 1.5 x 10-3 V

Question 12:  The flux linked with a coil at any instant t is given by: ∅ = 2t2 – t + 1. The magnitude of induced emf at t = 3 sec. is:

(a) 3.5 V

(b) 5 V

(c) 8 V

(d) 11 V

Question 13:  The magnetic flux threading a coil changes from 12 Wb to 6 Wb in 1 second. What is the value of induced emf?

(a) 3 volt

(b) ‒ 3 volt

(c) 6 volt

(d) ‒ 6 volt

Question 14: A copper rod of length l rotates about its end with angular velocity ω in a uniform magnetic filed B. What is the magnitude of emf developed between the ends of the rod?

(a) BωL2

(b) (BωL2)/2

(c) (BωL)/2

(d) None of these

Question 15: A coil of copper having 1000 turns is placed in a magnetic field (B = 4 × 10–5) perpendicular to its axis. The cross sectional area of the coil is 0.05 m2. If it turns through 180° in 0.01 second, then the e.m.f. induced in the coil will be ;

(a) 4 V
(b) 0.04 V
(c) 0.4 V
(d) 0.2 V

Question16:  The current in self inductance L = 40 mH is to be increased uniformly from 1 amp to 11 amp in 4 milliseconds. The e.m.f. induced in inductor during process is

(a) 100 volt
(b) 0.4 volt
(c) 4.0 volt
(d) 440 volt

Question 17:   An inductor may store energy in

(a) its electric field
(b) its coils
(c) its magnetic field
(d) both in electric and magnetic fields

Question 18: Direction of current induced in a wire moving in a magnetic field is found using

(a) Fleming’s left hand rule
(b) Fleming’s right hand rule
(c) Ampere’s rule
(d) Right hand clasp rule

Answer: (b) Fleming’s right hand rule

Question 19:  Lenz’s law is a consequence of the law of conservation of

(a) charge
(b) energy
(c) induced emf
(d) induced current

Question 20: A coil having 500 sq. loops of side 10 cm is placed normal to magnetic flux which increases at a rate of 1 T/s. The induced emf is

(a) 0.1 V
(b) 0.5 V
(c) 1 V
(d) 5 V

Question 21:  A coil of 100 turns carries a current of 5 mA and creates a magnetic flux of 10-5 weber. The inductance is

(a) 0.2 mH
(b) 2.0 mH
(c) 0.02 mH
(d) 0.002 H

Question 22:  A magnet is moved towards a coil (i) quickly (ii) slowly, then the induced e.m.f. is

(a) larger in case (i)
(b) smaller in case (i)
(c) equal in both the cases
(d) llarger or smaller depending upon the radius of the coil

Answer: (a) larger in case (i)

Question 23:   A current carrying infinitely long wire is kept along the diameter of a circular wire loop, without touching it, the correct statement(s) is(are)

I. The emf induced in the loop is zero if the current is constant.
II. The emf induced in the loop is finite if the current is constant.
III. The emf induced in the loop is zero if the current decreases at a steady rate

(a) I only

(b) II only

(c) I and II

(d) I, II and III

Question 24:  An induced e.m.f. is produced when a magnet is plunged into a coil. The strength of the induced e.m.f. is independent of

(a) the strength of the magnet
(b) number of turns of coil
(c) the resistivity of the wire of the coil
(d) speed with which the magnet is moved

Answer : (c) the resistivity of the wire of the coil

Question 25:  When current i passes through an inductor of self inductance L, energy stored in it is 1/2. L i2. This is stored in the

(a) current

(b) voltage

(c) magnetic field

(d) electric field

Question 26:  A magnet is moved towards a coil i) speedly  ii) slowly then induced emf/ induced charge will be respectively

(a) More in first case / more in first case

(b) More in first case / equal in both cases

(c) Less in first case / more in second case

(d) Less in first case / equal in both cases

Answer: (b) More in first case / equal in both cases

Question 27: In a coil of self inductance of 5 henry, the rate of change of current is 2 ampere per second, the e.m.f. induced in the coil is :

(a) 5 V
(b) – 5V
(c) – 10 V
(d) 10 V

Question 28: According to Lenz’s law there is a conversion of:

(a) momentum
(b) collision
(c) voltage
(d) energy

Question 29:  A solenoid is connected to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, the current will

(a) increase
(b) decrease
(c) remain same
(d) first increase then decrease

Question 30: Which of the following statements is not correct?

(a) Whenever the amount of magnetic flux linked with a circuit changes, an emf is induced in circuit.
(b) The induced emf lasts so long as the change in magnetic flux continues.
(c) The direction of induced emf is given by Lenz’s law.
(d) Lenz’s law is a consequence of the law of conservation of momentum.

Answer: (d) Lenz’s law is a consequence of the law of conservation of momentum.

Question 31:  There is a uniform magnetic field directed perpendicular and into the plane of the paper. An irregular shaped conducting loop is slowly changing into a circular loop in the plane of the paper. Then

(a) current is induced in the loop in the anti-clockwise direction.
(b) current is induced in the loop in the clockwise direction.
(c) ac is induced in the loop.
(d) no current is induced in the loop.

Answer: (a) current is induced in the loop in the anti-clockwise direction.

Question 32:  Two identical coaxial coils P and Q carrying equal amount of current in the same direction are brought nearer. The current in

(a) P increases while in Q decreases
(b) Q increases while in P decreases
(c) both P and Q increases
(d) both P and Q decreases

Answer: (a) P increases while in Q decreases

Question 33:  Direction of current induced in a wire moving in a magnetic field is found using

(a) Fleming’s left hand rule
(b) Fleming’s right hand rule
(c) Ampere’s rule
(d) Right hand clasp rule

Answer: (b) Fleming’s right hand rule

Question 34:  The self inductance associated with a coil is independent of

(a) current

(b) time

(c) induced voltage

(d) resistance of coil

Question 35:  The plane in which eddy currents are produced in a conductor is inclined to the plane of the magnetic field at an angle equal to

(a) 45°

(b) 0°

(c) 180°

(d) 90°

Question 36:  What is increased in step down transformer?

(a) Voltage

(b) Current

(c) Power

(d) Current density

Question 37: In a transformer, number of turns in the primary coil are 140 and that in the secondary coil are 280. If current in primary is 4 A then that in secondary is

(a) 4 A

(b) 2 A

(c) 6 A

(d) 10 A

Question 38:  The magnetic field is parallel to a surface, then the magnetic flux through the surface is :

(a) zero
(b) small but not zero
(c) infinite
(d) large but not infinite

Answer: (b) small but not zero

Question 39:  The self-inductance L of a solenoid of length l and area of cross-section A, with a fixed number of turns N increases as

(a)  l and A increase.
(b)  l decreases and A increases.
(c)  l increases and A decreases.
(d)  both l and A decrease.

Answer: (b)  l decreases and A increases.

Question 40:  In the second experiment, Faraday replaced ‘X’ with ‘Y’ for checking the deflection in the galvanometer. Identify X and Y.

(a)   X ➔ Current carrying coil; Y ➔ Bar magnet
(b)  X ➔ Bar magnet; Y ➔ Current carrying coil
(c)   X ➔ Bar magnet; Y ➔ Battery
(d)  X ➔ Current carrying coil; Y ➔ Battery

Answer: (b)  X ➔ Bar magnet; Y ➔ Current carrying coil

Question 41: The north pole of a bar magnet is rapidly introduced into a solenoid at one end (say A). Which of the following statements correctly depicts the phenomenon taking place?

(a) No induced emf is developed.
(b) The end A of the solenoid behaves like a south pole.
(c) The end A of the solenoid behaves like north pole.
(d) The end A of the solenoid acquires positive potential.

Answer: (c) The end A of the solenoid behaves like north pole.

Question 42:  A metal plate can be heated by
(a) passing either a direct or alternating current through the plate.
(b) placing in a time varying magnetic field.
(c) placing in a space varying magnetic field, but does not vary with time.
(d) both (a) and (b) are correct.

Answer: (d) both (a) and (b) are correct.

Question 43: Which of the following statements is not correct?

(a) Whenever the amount of magnetic flux linked with a circuit changes, an emf is induced in circuit.
(b) The induced emf lasts so long as the change in magnetic flux continues.
(c) The direction of induced emf is given by Lenz’s law.
(d) Lenz’s law is a consequence of the law of conservation of momentum.

Answer: (d) Lenz’s law is a consequence of the law of conservation of momentum.

Question 44: There is a uniform magnetic field directed perpendicular and into the plane of the paper. An irregular shaped conducting loop is slowly changing into a circular loop in the plane of the paper. Then

(a) current is induced in the loop in the anti-clockwise direction.
(b) current is induced in the loop in the clockwise direction.
(c) ac is induced in the loop.
(d) no current is induced in the loop.

Answer: (a) current is induced in the loop in the anti-clockwise direction.

Question 45: The north pole of a bar magnet is rapidly introduced into a solenoid at one end (say A). Which of the following statements correctly depicts the phenomenon taking place?

(a) No induced emf is developed.
(b) The end A of the solenoid behaves like a south pole.
(c) The end A of the solenoid behaves like north pole.
(d) The end A of the solenoid acquires positive potential.

Answer: (c) The end A of the solenoid behaves like north pole.

Question 46: Eddy currents are produced when

(a) A metal is kept in varying magnetic field
(b) A metal is kept in the steady magnetic field
(c) A circular coil is placed in a magnetic field
(d) Through a circular coil, current is passed

Answer :  (a) A metal is kept in varying magnetic field

Question 47: The coefficient of self-inductance of a solenoid is 0.18 mH. If a rod of soft iron of relative permeability 900 is inserted, then the coefficient of self-inductance will become nearly

(a) 5.4 mH
(b) 162 mH
(c) 0.006 mH
(d) 0.0002 mH

Question 48: In an AC generator, a coil with N turns, all of the same area A and total resistance R, rotates with frequency w in a magnetic field B. The maximum value of emf generated in the coil is

(a) N.A.B.R.w
(b) N.A.B.
(c) N.A.B.R.
(d) N.A.B.w

Question 49: A conducting ring of radius 1 metre is placed in an uniform magnetic field B of 0.01 tesla oscillating with frequency 100 Hz with its plane at right angle to B. What will be the induced electric field ?

(a) pvolt /m
(b) 2volt /m
(c) 10 volt/m
(d) 62 volt/m

Question 50: A charged particle moves through a magnetic field in a direction perpendicular to it. Then the

(a) velocity remains unchanged
(b) speed of the particle remains unchanged
(c) direction of the particle remains unchanged
(d) acceleration remains unchanged

Answer : (b) speed of the particle remains unchanged

-: End of Electromagnetic Induction MCQ Type Questions for ISC Physics Class-12 :-

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