electric current and magnetism - Category wise Question and Answer Practice Test with Solutions

Question : 6 [IAS Prelim]

Consider the following statements: An ordinary light bulb has a rather short life because the:

1. filament wire is not uniform.
2. bulb cannot be evacuated completely.
3. wires supporting the filament melt at high temperatures.

a) 1 and 2

b) 1 and 3

c) 2 and 3

d) 1, 2 and 3

Question : 7

At the time of short circuit, the current in the circuit

a) does not change

b) increases heavily

c) reduces substantially

d) vary continuously

Question : 8

Transformers are used

a) in AC circuits only

b) in both DC and AC circuits

c) in DC circuits only

d) neither in DC nor in AC circuits

Question : 9

To convert mechanical energy into electrical energy, one can use

a) AC dynamo

b) DC dynamo

c) motor

d) Both (a) & (b)

Question : 10

From a power station, the power is transmitted at a very high voltage because –

a) it is cheaper to produce electricity at high voltage

b) electricity at high voltage is less dangerous

c) it is generated only at high voltage

d) there is less loss of energy in transmission at high voltage