Question

Given below are two statements:

Statement-I : Susceptibilities of paramagnetic and ferromagnetic substances increase with decrease in temperature.

Statement-II : Diamagnetism is a result of orbital motions of electrons developing magnetic moments opposite to the applied magnetic field.

Choose the correct answer from the options given below:-

• A. Both Statement-I and Statement-II are true
• B. Both Statement-I and Statement-II are false
• C. Statement-I is true but Statement-II is false
• D. Statement-I is false but Statement-II is true

Answer 1

The Correct Option is A

To determine the correctness of the given statements, let's explore them one by one:

1. Statement-I: Susceptibilities of paramagnetic and ferromagnetic substances increase with decrease in temperature.

This statement is analyzed using Curie's Law, which states:

\chi = \frac{C}{T}

Here, \chi is the magnetic susceptibility, C is the Curie constant, and T is the absolute temperature. According to this relation, as temperature T decreases, the susceptibility \chi of paramagnetic substances increases, supporting Statement-I.

• Ferromagnetic materials, below their Curie temperature, show a significant susceptibility that generally increases as the temperature decreases, due to alignment of magnetic domains.

Hence, Statement-I is true.

2. Statement-II: Diamagnetism is a result of orbital motions of electrons developing magnetic moments opposite to the applied magnetic field.

Diamagnetism is indeed a property of all materials and is due to the orbital motion of electrons creating tiny current loops, which produce magnetic moments. When an external magnetic field is applied, these magnetic moments are aligned in opposition to the field.

This is consistent with the behaviour described in Statement-II, affirming its truth.

Therefore, both statements accurately describe real physical phenomena:

• Statement-I correctly describes the temperature-dependent behavior of susceptibility in paramagnetic and ferromagnetic materials.
• Statement-II accurately captures the fundamental nature of diamagnetism.

Thus, the correct option is: Both Statement-I and Statement-II are true.