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

Question : 21

On charging by conduction, mass of a body may

a) decreases

b) increase or decrease

c) increase

d) none of these

Question : 22 [PCS (Pre) 2014]

A wire with black insulation during electric supply is

a) Neutral wire

b) Live wire

c) Earth wire

d) Fuse wire

Question : 23

If the conductivity of a semiconductor is only due to break up of the covalent bonds due to thermal excitation, then the semiconductor is called

a) extrinsic

b) donor

c) intrinsic

d) acceptor

Question : 24

Which one of the following is not a correct statement about semiconductors?

a) In an n-type semiconductor, the Fermi level lies closer to the conduction band edge

b) Silicon is a direct band gap semiconductor

c) The electrons and holes have different mobilities in a semiconductor

d) Silicon is has diamond structure