• # question_answer Dictate different expressions obtained through Curie law in magnetism. Represent these expressions through graphs also. A saturation region is obtained in one of the graphs, why?

Curie discovered experimentally that, the intensity of magnetisation (I) of a paramagnetic substance is directly proportional to external field ${{B}_{0}}$and inversely proportional to the absolute temperature (T) of the material. Mathematically,             $I\propto {{B}_{0}}/T\Rightarrow I=C{{B}_{0}}/T$ where, C is known as Curie constant. Variation of intensity of magnetisation with ${{\mathbf{B}}_{\mathbf{0}}}\mathbf{/T}$ We know that,    $B={{\mu }_{0}}H$ $\therefore$      $I=C{{\mu }_{0}}H/T\Rightarrow I=KH/T$ where,   $K={{\mu }_{0}}C=$ another constant $\therefore$      $\frac{1}{H}=\frac{K}{T}\Rightarrow \chi =\frac{K}{T}$            $\left[ \because \chi =\frac{1}{H} \right]$ i.e.        $\chi \propto \frac{1}{T}$ In the variation of intensity of magnetisation with ${{B}_{0}}/T$ a saturation region is obtained. At a particular stage, all the atomic dipoles present in the specimen align in the direction of the external field and this leads to saturation region.