(A) voltage
(B) current
(C) frequency
(D) Both (a) & (b)
Tag: Physics Mcqs
The core of a transformer is laminated to reduce:
(A) copper loss
(B) magnetic loss
(C) eddy current loss
(D) hysteresis loss
The core of transformer is laminated so that:
(A) The core of transformer is laminated so that:
A) The ratio of the voltage in the secondary to that in the primary may be increased
(B) Energy losses due to eddy currents may be minimized
(C) The weight of the transformer may be reduced
(D) Rusting of the core may be prevented
Energy stored in the choke coil in the form of:
(A) heat
(B) electricity energy
(C) magnetic energy
(D) electro-magnetic energy
27 If the rotational velocity of a dynamo armature is doubled, then the induced e.m.f will be:
(A) become half
(B) become double
(C) become quadruple
(D) remain unchanged
Quantity that remains unchanged in a transformer is:
(A) voltage
(B) current
(C) frequency
(D) Both (a) & (b)
If the emf induced in a coil is 200 V when the current changes from 1 a to 2 A in 0.05s , the self-inductance of the coil is:
(A) 1 H
(B) 10 H
(C) 20 H
(D) 30 H
A step-up transformer is used on a 120 V line to provide a potential difference of 2400 V. If the primary coil has 75 turns, the number of turns in the secondary coil is:
(A) 1500
(B) 1200
(C) 150
(D) 1575