Paramagnetic Magnetisation and Temperature – Rankers Physics

Magnetic Properties of Matter: Practice Problem & Solution

Assertion (A): A paramagnetic sample shows greater degree of magnetisation when cooled. Reason (R): Magnetisation of paramagnetic material is inversely proportional to temperature.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Magnetic Properties of Matter. Understanding the underlying formula is key to arriving at the correct answer below:

According to Curie's Law, the magnetic susceptibility \(\chi\) of a paramagnetic material is inversely proportional to its absolute temperature \(T\) (i.e., \(\chi \propto \frac{1}{T})\). Thus, cooling (decreasing \(T\)) increases magnetisation. Both assertion and reason are true, and the reason correctly explains the assertion.

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