## H C VERMA PHYSICS BOOK SOLUTIONS MAGNETIC PROPERTIES OF MATTER

Solved Examples

Example 37.1   A bar magnet made of steel has a magnetic moment of 2.5 A–m2 and a mass of 2.5 A–m2

and a mass of 6.6 × 103 kg. If the density of steel is 7.9 × 10 3 kg/m3 , find the intensity

of magnetization of the magnet.

Example 37.2    Find the magnetic intensity H at the centre of a long solenoid having n turns per unit

length and carrying a current i

(a) when no material is kept in it and

(b) when a long copper rod is inserted in the solenoid.
Sol.

(b) As the solenoid and the rod are long and we are interested in the magnetic intensity at the centre,

the end effects may be neglected. There is no effect of the rod on the magnetic intensity at the centre.

Its value in both cases are the same. Thus H = ni.

Example 37.3    Find the per cent increase in the magnetic field B when the space withhin a

current–carrying toroid is filled with aluminium. The susceptibility of aluminium is 2.1 × 10  – 5 .

Sol.

Objective - I

1.   A perpendicular material is place in a magnetic fields. Consider the following statemetns;
(A) If the magnetic field is increased, the magnetization is increased.
(B) If the temperature is increased, the magnetization is increased