Question

The magnetic susceptibility is negative for :

• A. paramagnetic material only
• B. ferromagnetic material only
• C. paramagnetic and ferromagnetic materials
• D. diamagnetic material only

Answer 1

The Correct Option is D

The question asks us to identify the material for which the magnetic susceptibility is negative. To solve this, we need to understand the concept of magnetic susceptibility in different types of magnetic materials. Magnetic susceptibility (\chi) is a measure of how much a material will become magnetized in an applied magnetic field.

1. Paramagnetic Materials: These materials have a small and positive magnetic susceptibility. In paramagnetic materials, the magnetic dipoles tend to align with the applied magnetic field, increasing the field inside the material. Consequently, their magnetic susceptibility is positive.
2. Ferromagnetic Materials: Similar to paramagnetic materials, ferromagnetic materials also have a magnetic susceptibility that is positive. However, in ferromagnetic materials, the alignment of magnetic domains is much stronger, leading to a significantly higher magnetic susceptibility.
3. Diamagnetic Materials: These materials have a negative magnetic susceptibility. Diamagnetic materials create an induced magnetic field in a direction opposite to that of the applied magnetic field. This weak, repulsive effect results in a negative magnetic susceptibility.

Given these explanations, the material type with negative magnetic susceptibility is exclusively the diamagnetic material.

Conclusion: The correct answer is diamagnetic material only. This is because diamagnetic materials create a magnetic field in opposition to the applied external magnetic field, leading to negative magnetic susceptibility.

Hence, the correct answer is:

Option: diamagnetic material only