Question

The magnetic susceptibility of a paramagnetic substance at $-{173}^o$C is $1.5\times {10}^{-2}$ then its value at $-{73}^o$C will be.

• A. $7.5\times {10}^{-1}$
• B. $7.5\times {10}^{-2}$
• C. $7.5\times {10}^{-3}$
• D. $7.5\times {10}^{-4}$

Answer 1

The correct option is C $7.5\times {10}^{-3}$

Given that

$X_1=0.015at{T}_1=-{173}^o$ and $T_2=-{73}^{o}C$$

According to Curie's Law:-

$X=\frac{C}{T}$ where $C$ is constant

$⟹X_1\propto \frac{1}{T_1}$

$\therefore \frac{X_2}{X_1}=\frac{T_1}{T_2}$

$⟹X_2=X_1\times \frac{T_1}{T_2}=0.015\times \frac{273-173}{273-73}=0.0075$

$\therefore$ Magnetic susceptibility of a paramagnetic material at $-{73}^o$ is $7.5\times {10}^{-3}$