Electromagnetic Induction Class 12 MCQs Questions with Answers

1. 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:

2. 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:

3. An e.m.f is produced in a coil, which is not connected to an external voltage source. This is not due to

4. The coupling co-efficient of the perfectly coupled coils is:

5. A choke is used as a resistance in :

6. 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 :

7. Which of the following is/are equal to Henry?

8. Direction of current induced in a wire moving in a magnetic field is found using

9. Faraday’s laws are consequence of the conservation of

10. Eddy currents do not cause

11. Induced e.m.f. produced in a coil rotating in a magnetic field will be maximum when the angle between the axis of coil and direction of magnetic field is:

12. 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

13. 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

14. When the magnetic field is parallel to a surface, then the magnetic flux through the surface is:

15. When the rate of change in current is unity, the induced emf is equal to

16. Two inductors of inductance .L each are connected in series with opposite? magnetic fluxes. The resultant inductance is (Ignore mutual inductance)

17. Which of the following is based on the law of conservation of energy?

18. 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?

19. Faraday’s laws are consequence of the conservation of

20. A metal plate can be heated by