## Class 12 Physics MCQs Electromagnetic Induction for JEE/NEET

Here, you will get Class 12 Physics MCQ of Chapter 6 Electromagnetic Induction for cracking JEE and NEET/AIIMS. By solving these MCQs of Class 12 Physics Chapter 6 Electromagnetic Induction, you will get the confidence to crack JEE or NEET. Practice MCQ Questions for Class 12 Physics with Answers on a daily basis and score well in exams.

## Electromagnetic Induction Class 12 MCQs Questions with Answers

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

An e and a p are moving parallel to each other in a magnetic field. The magnetic force acting on the p+ is
(a) 1840 times that on e
(b) less than that of e
(c) same as that of e
(d) slightly more than that of e

Answer: (c) same as that of e–

Two coils of self inductance 2 mil and 8 mil are placed so close together that the effective flux in one coil is completely linked with other. The mutual inductance between these coils is
(a) 4 mH
(b) 16 mH
(c) 10 mH
(d) 6 mH

A transformer is used to light 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 A. Then the efficiency of the transformer is
(a) 11%
(b) 50%
(c) 80%
(d) 90%

The magnetic flux (∅) linked with a coil is related to the number of turns (N) of the coil as
(a) f ∝ N
(b) f ∝ N-1
(c) f ∝ N2
(d) f ∝ N-2

Which of the following gives the direction of the induced e.m.f.?
(b) Lenz’s law
(c) Ampere
(d) Biot-Savart’s law

The electric current in a circuit varies from + 2A to – 2A in a time 10-2 s. Another coil of resistance 20 Ω and inductance 2H is placed hear it. What will be the induced current in the second coil?
(a) 4A
(b) 8A
(c) 20A
(d) 40A

Which of the following instrument do not make use of eddy currents?
(a) Electrical brakes
(c) inductor motor
(d) Transformer

What voltage is developed across the axle of the wheels of a train, when it moves with a speed of 72 kmh-1? The horizontal component of earth’s magnetic field is 0.40 × 10-4 T and the angle of dip is 30°. The length of the axle is 1.5 m.
(a) 0.8 mv
(b) 0.4 mv
(c) 0.2 mv
(d) 0.7 mv

The magnetic flux (∅) lined with a coil is related to its area (s) as
(a) ∅ ∝ s
(b) ∅ ∝ s²
(c) ∅ ∝ s1/2
(d) ∅ ∝ s-1/2

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

In a coil of self-induction 5 H, the rate of change of current is 2 As-1. Then emf induced in the coil is
(a) 10 V
(b) -10 V
(c) 5 V
(d) -5 V

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

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

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

A metal conductor of length 1 m rotates vertically about one of its ends at angular velocity 5 rad s-1 . If the horizontal component of earth’s magnetism is 2 × 10-5 T, then e.m.f. developed between the two ends of the conductor is
(a) 5 µV
(b) 50 µV
(c) 5 mV
(d) 50 mV

A car moves up on a plane road. The induced e.m.f. in the axle connecting the two wheels is maximum, when it moves
(a) At the poles
(b) At equator
(c) remains stationary
(d) No e.m.f. is induced at all

Which of the following is/are equal to Henry?
(a) Volt second/ampere.
(b Volt(second)²/coulomb.
(c) Joule (second)²/(coulomb)²
(d) All of these

A copper rod moves parallel to the horizontal direction. The induced e.m.f. developed across its ends due to earth’s magnetic field will be maximum at the
(a) poles
(b) equator
(c) latitude 30°
(d) latitude 60°.

Which of the following does not use the application of eddy current?
(a) Electric power meters
(b) Induction furnace
(c) LED lights
(d) Magnetic brakes in trains

Two inductors of inductance .L each are connected in series with opposite? magnetic fluxes. The resultant inductance is
(Ignore mutual inductance)
(a) zero
(b) L
(c) 2L
(d) 3L

A square of side L metres lies in the x-y plane in a region, where the magnetic field is given by B = B0{li + 3j + 4k) T, where Bo is constant. The magnitude of flux passing through the square is
(a) 2BoL² Wb
(b) 3BoL² Wb
(c) 4BoL² Wb
(d) √29 BoL² Wb

If I current is flowing inductance L, then the dimension of 32 LI² is equivalent to
(a) charge
(b) force
(c) momentum
(d) energy

For purely capacitive circuits, power factor is
(a) 0
(b) -1
(c) 1
(d) infinity