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

Question : 11

The mobility of conduction electrons is greater than that of holes, since electrons

a) are negatively charged

b) require smaller energy for moving through crystal lattice

c) are lighter

d) undergo smaller number of collisions

Question : 12 [BPSC (Pre) 2005]

How does the white light produce in the tube?

a) To accelerate the atoms

b) To heat up the copper wire

c) To heat up the filament

d) To oscillate molecule

Question : 13

Curie temperature is the temperature above which

a) a ferromagnetic material becomes diamagnetic

b) a ferromagnetic material becomes paramagenetic

c) a paramagnetic material becomes diamagnetic

d) a paramagnetic m aterial becomes ferromagnetic

Question : 14

The core of a transformer is laminated because

a) ratio of voltage in primary and secondary may be increased

b) the weight of the transformer may be reduced

c) rusting of the core may be prevented

d) energy losses due to eddy currents may be minimised

Question : 15

At absolute zero, Si acts as

a) metal

b) insulator

c) non-metal

d) None of these