Question

The magnetic susceptibility of a paramagnetic material at $-73^{\circ }C$ is $0.0075$, its value at $-173^{\circ }C$ will be

• A. $0.0045$
• B. $0.0030$
• C. $0.0150$
• D. $0.0075$

Answer 1

Answer: (C)

Here, ${\chi }_{ml}=0.0075$,
$T_1=-73^{\circ }C=\left(-73+273\right)K=200K$
${\chi }_{m_2}=?,T_2=-173^{\circ }C=\left(-173+273\right)K=100K$
For paramagnetic material, magnetic susceptibility
${\chi }_m\propto \frac{1}{T}\Rightarrow \frac{{\chi }_{m_2}}{{\chi }_{m_1}}=\frac{T_1}{T_2}=\frac{200}{100}=2$
$\therefore {\chi }_{m_2}=2{\chi }_{m_1}=2\times 0.0075$
$=0.0150$