set 9 MCQ Questions & Answers Detailed Explanation

Question : 1

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 : 2

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 : 3

Which of the following is an artificial magnet?

a) Magnetic needle

b) Bar magnet

c) Horse-shoe magnet

d) All of the above

Question : 4

What gases are filled in fluorescent tube?

a) Mercury

b) Neon

c) Sodium

d) Mercury and neon

Question : 5

The current in the armature of a motor is reversed at every half cycle due to the action of a(n)

a) field coil

b) brush

c) armature

d) commutator

Question : 6

Electromagnets are made of soft iron because soft iron has

a) low retentivity and low coercive force

b) low retentivity and high coercive force

c) high retentivity and high coercive force

d) high retentivity and low coercive force