Question

A paramagnetic material is placed in a magnetic field. Consider the following statements:
(A) If the magnetic field is increased, the magnetisation is increased.
(B) If the temperature is increased, the magnetisation is increased.
(a) A and B are true.
(b) A is true but B is false.
(c) B is true but A is false.
(d) A and B are false.

Answer 1

(b) A is true but B is false.

if the magnetic field is increased, magnetisation of paramagnetic material placed in magnetic field is also increases. Hence, option (a) is correct.

Magnetization (I) is given by,
$\overrightarrow{I}=\frac{\overrightarrow{M}}{V}$
As the temperature is increased, magnetic moments of paramagnetic material becomes more randomly aligned due to incresed thermal motion. This leads decrease in the magnetization I. Hence, option (b) is incorrect.