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

Question : 11

When a forward bias is applied to a p-n junction, it

a) reduces the majority carrier current to zero.

b) lowers the potential barrier.

c) raises the potential barrier.

d) None of these

Question : 12

Two spheres A and B of exactly same mass are given equal positive and negative charges respectively. Their masses after charging

a) mass of A > mass of B

b) mass of A < mass of B

c) remains unaffected

d) nothing can be said

Question : 13 [NDA]

Which one of the statements given below is not correct?

a) The degree to which the magnetic field can penetrate a medium is known as the relative permeability of the medium

b) A vertical plane passing through the axis of a freely suspended magnet is called the magnetic meridian

c) A vertical plan passing through the axis of rotation of the Earth is called the geographical meridian

d) The relative permeability is not a dimensionless quantity

Question : 14

Which of the following is an artificial magnet?

a) Magnetic needle

b) Bar magnet

c) Horse-shoe magnet

d) All of the above

Question : 15 [NDA]

Which one among the following is used to make periscope?

a) Plane mirror

b) Concave lens

c) Concave mirror

d) None of the above