Question

The magnetic susceptibility \( \chi \) of paramagnetic substance varies with absolute temperature \( T \) as:

• A. \( \chi \propto T \)
• B. \( \chi \propto T^{-1} \)
• C. \( \chi \propto \sqrt{T} \)
• D. \( \chi \propto T^2 \)

Hint:

For paramagnetic substances, magnetic susceptibility varies inversely with temperature, following Curie's law \( \chi \propto \frac{1}{T} \).

Answer 1

The Correct Option is A

In paramagnetic materials, the magnetic susceptibility \( \chi \) is a measure of the material’s response to an applied magnetic field. According to Curie's law, the magnetic susceptibility of a paramagnetic substance is inversely proportional to the temperature \( T \), given by:
\[ \chi = \frac{C}{T} \] Where: - \( \chi \) is the magnetic susceptibility,
- \( C \) is the Curie constant,
- \( T \) is the absolute temperature.
Curie’s law implies that as temperature increases, the magnetic susceptibility of a paramagnetic substance decreases. This is because at higher temperatures, the thermal motion of the atoms tends to oppose the alignment of magnetic moments with the applied field, reducing the susceptibility.
This relationship shows that the magnetic susceptibility is inversely proportional to the temperature, meaning:
\[ \chi \propto \frac{1}{T} \] Therefore, the correct answer is option (A) \( \chi \propto T \).