The magnetic susceptibility of a paramagnetic material at \( -73^{\circ} \mathrm{C} \) is \( 0.0075 \) and its value at
\( -173^{\circ} \mathrm{C} \) will be

Given, magnetic susceptibility of para-magnet at \(T_{1}=73^{\circ} \mathrm{C}\)
is \(0.0075\)
Let magnetic susceptibility at \(T_{2}=-173^{\circ} \mathrm{C}\) be \(\chi_{2}\)
We know magnetic susceptibility is given by \(\chi \propto \frac{1}{T}\)
Therefore,
\(\frac{\chi_{1}}{\chi_{2}}=\frac{T_{2}}{T_{1}} \Rightarrow \frac{0.0075}{\chi_{2}}=\frac{-173^{\circ} \mathrm{C}}{-73^{\circ} \mathrm{C}}\)
\(\Rightarrow \frac{0.0075}{\chi_{2}}=\frac{(273-173) K}{(273-73) K} \Rightarrow \frac{0.0075}{\chi_{2}}=\frac{100}{200}\)
\(\Rightarrow \frac{0.0075}{\chi_{2}}=\frac{1}{2} \Rightarrow \chi_{2}=2 \times 0.0075=0.0150\)
Therefore, magnetic susceptibility at \(-173^{\circ} \mathrm{C}\) will be \(0.0150\).