Question

A paramagnetic material has magnetic susceptibility of $3.3\times {10}^{-4}$ at $300\text{K}$. Its susceptibility at $350\text{K}$ is

• A. $2.8\times {10}^{-4}$
• B. $2.6\times {10}^{-4}$
• C. $3.2\times {10}^{-4}$
• D. $2.4\times {10}^{-4}$

Answer 1

The correct option is A $2.8\times {10}^{-4}$

According to Curie's law for paramagnetic substance,

$$\chi \propto \frac{1}{T_c}.....\left(1\right)$$

Given,
${\chi }_1=3.3\times {10}^{-4};T_{c_1}=300\text{K};T_{c_2}=350\text{K}$

Where, $T_c$ is curie temperature

Using (1) we get,

$\frac{{\chi }_2}{{\chi }_1}=\frac{T_{c_1}}{T_{c_2}}$

$\Rightarrow \frac{{\chi }_2}{3.3\times {10}^{-4}}=\frac{300}{350}$

${\chi }_2=\frac{6}{7}\times 3.3\times {10}^{-4}=\frac{19.8}{7}\times {10}^{-4}$

${\chi }_2=2.8\times {10}^{-4}$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(B\right)$ is the correct answer.