Question

The magnetic susceptibility of a paramagnetic substance at $-173^{\circ }C$ is $1.5\times 10^{-2}$. If its value at $-73^{\circ }C$ is $b\times 10^{-3}$, then find $b$.

Answer 1

Answer: 7.50

In paramagnetic substance, the magnetic susceptibility is given by
$\chi =\frac{C}{T}\Rightarrow \frac{{\chi }_1}{{\chi }_2}=\frac{T_2}{T_1}$
Then ${\chi }_2={\chi }_1\times \frac{T_1}{T_2}$
Here, ${\chi }_1=1.5\times 10^{-2}$,
$T_1=273-173=100K$
$T_2=273-73=200K$
$\therefore {\chi }_2=1.5\times 10^{-2}\times \frac{100}{200}$
$=7.5\times 10^{-3}$