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

Question : 26 [RAS/RTS (Pre) 2013]

A device which converts chemical energy into electrical energy is called

a) Generator

b) Battery

c) Motor

d) Moving coil meter

Question : 27

In an unbiased p-n junction, holes diffuse from the p-region to n-region because

a) they move across the junction by the potential difference.

b) hole concentration in p-region is more as compared to n-region.

c) free electrons in the n-region attract them.

d) all the above

Question : 28

Kilowatt-hour is the unit of

a) electric power

b) electrical energy

c) potential difference

d) charge

Question : 29 [BPSC (Pre) 1999]

Principle of fuse is

a) Heating effect of electricity

b) Chemical effect of electricity

c) Mechanical effect of electricity

d) Magnetic effect of electricity

Question : 30

An n-p-n transistor conducts when

a) both collector and emitter are positive with respect to the base

b) collector is positive and emitter is negative with respect to the base

c) both collector and emitter are negative with respect to the base

d) collector is positive and emitter is at same potential as the base