Question

Above the curie temperature the susceptibility of a ferromagnetic substance varies

• A. directly as the absolute temperature.
• B. inversely as the absolute temperature.
• C. inversely as the square root of absolute temperature.
• D. directly as the square root of absolute temperature.

Hint:

Curie's law describes the variation of susceptibility with temperature above the Curie point, where the susceptibility decreases with increasing temperature.

Answer 1

The Correct Option is B

Step 1: Understanding Curie’s law.
Curie's law states that the magnetic susceptibility \( \chi \) of a ferromagnetic material above the Curie temperature \( T_C \) is inversely proportional to the temperature \( T \), i.e., \[ \chi \propto \frac{1}{T - T_C} \]
Step 2: Analyzing the options.
- (A) Directly as the absolute temperature is incorrect because susceptibility decreases with increasing temperature. - (B) Inversely as the absolute temperature is correct, as per Curie’s law. - (C) Inversely as the square root of absolute temperature is incorrect for this situation. - (D) Directly as the square root of absolute temperature is also incorrect.

Step 3: Conclusion.
The correct answer is (B), as susceptibility varies inversely with temperature above the Curie temperature.