# Physics Class-12 Chapter-6 Electromagnetic Induction Most VVI Important Questions

Q.1. Lenz’s law is associated with

(A) charge

(B) mass

(C) energy

(D) principle of conservation of momentum

Ans:- (C)

Q.2. The working of dynamo is based on the principle of

(A) heating effect of current

(B) electromagnetic induction

(C) magnetic induction

(D)  Electric induction

Ans:- (B)

Q.3. Unit of self induction is

(A) weber

(B) Ohm

(C) Henry

(D) Gauss

Ans:- (C)

Q.4. Direction of Eddy current is obtained using

(A) kirchhoff’s laws

(B) Lenz’s law

(C) planck’s law

(D) none of these

Ans:- (B)

Q.5. Transformer works in case of

(A) only d.c.

(B) only a.c.

(C) both a.c. and d.c.

(D) none of these

Ans:- (B)

Q.6. The material most appropriate for core of a transformer is

(A) soft iron

(B) copper

(C) stainless steel

(D) alnico

Ans:- (A)

Q.7. The self inductance of a coil is 5 mH. If a current of 2 A is passed, the magnetic flux linked with the coil will be

(A) 1Wb

(B) 0.1 Wb

(C) 0.01 Wb

(D) 0.001 Wb

Ans:- (C)

Q.8. Two inductors each of inductance L are joined in parallel. Their equivalent inductance is

(A) 2L

(B) L/2

(C) L

(D) zero

Ans:- (B)

Q.9. If an inductor having inductance L is joined to another identical inductor with its one end  joined, the resultant inductance would become

(A) 2L

(B) L/2

(C) zero

(D) L/4

Ans:- (A)

Q.10. If there are N₁ and N₂ turns in the primary and secondary coils respectively in a step down transformer, then

(A) N₁ > N₂

(B) N₂ > N₁

(C) N₁ = N₂

(D) N₁=0

Ans:- (A)

Q.11. Eddy current can provide

(A) retardation in speed

(B) heat

(C) separation of metals from nonmetals

(D) all of these

Ans:- (D)

Q.12. Maglev is used in

(A) railways

(B) cars

(C) aeroplanes

(D) none of these

Ans:- (A)

Q.13. The law governing electromagnetic induction is called

(A) Newton’s law

(C) Ohm’s law

(D) Ampere’s law

Ans:- (B)

Q.14. Lenz’s law is a consequence of the law of conservation of

(A) Charge

(B) energy

(C) mass

(D) mementum

Ans:- (B)

Q.15. If the number of turns per unit length of a coil of solenoid is doubled, the self inductance of the solenoid will

(A) remains unchanged

(B) becomes four times

(C) be doubled

(D) be halved

Ans:- (B)

Q.16. Two coils are placed closed to each other. the mutual inductance of the pair of coils depend on

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

(B) relative positions and orientations of the two coils

(C) the material of the wires of the coils

(D) the currents in the two coils

Ans:- (B)

Q.17. Volt is the unit of

(A) induced EMF

(B) induced current

(C) potential difference

(D) both A and C

Ans:- (D)

Q.18. An electric motor

(A) creates mechanical energy

(B) creates electrical energy

(C) converts mechanical energy to electrical energy

(D) converts electrical energy to mechanical energy

Ans:- (D)

Q.19. A dynamo

(A) creates mechanical energy

(B) create electrical energy

(C) converts mechanical energy to electrical energy

(D) converts electrical energy to mechanical energy

Ans:- (C)

Q.20. An inductor may store energy in its

(A) electric field

(B) coil

(C) magnetic field

(D) none of these

Ans:- (C)

Q.21. The working of an induction coil is based on the principle of

(A) electric induction

(B) magnetic induction

(C) electricromagnetic induction

(D) none of these

Ans:- (C)

Q.22. If a Magnet is allowed to fall through a metal ring. then during the fall the acceleration is

(A) equal to g

(B) less than g

(C) more than g

(D) none of these

Ans:- (B)

Q.23. If the speed of rotation  of the armature of a generator is increased, the maximum EMF produced will be

(A) decreases

(B) increases

(C) remains constant

(D) none of these

Ans:- (B)