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
(B) Faraday’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)