Question

If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted ny $\mu_d, \mu_p$ and $\mu_f$ respectively, then

• A. $\mu_d=0$ and $\mu_p \ne 0$
• B. $\mu_d \ne 0$ and $\mu_p = 0$
• C. $\mu_p=0$ and $\mu_f \ne 0$
• D. $\mu_d = 0$ and $\mu_f \ne 0$

Answer 1

The Correct Option is A

To understand the behavior of materials under the influence of a magnetic field, we need to consider the magnetic dipole moments of different types of magnetic materials: diamagnetic, paramagnetic, and ferromagnetic.

1. Diamagnetic Materials: These materials create an induced magnetic field in a direction opposite to that of an externally applied magnetic field, thus leading to a very weak repulsion by the magnetic field. Importantly, a key characteristic of diamagnetic materials is that they have no inherent magnetic dipole moments. Consequently, the net magnetic dipole moment $\mu_d$ of a diamagnetic atom is zero. Hence, $\mu_d = 0$.
2. Paramagnetic Materials: These materials contain unpaired electrons, leading to non-zero individual atomic magnetic moments. These moments can align with an external magnetic field, resulting in a net magnetic dipole moment in the direction of the field. Therefore, for paramagnetic materials, $\mu_p \ne 0$.
3. Ferromagnetic Materials: These materials have magnetic moments that can be aligned in the same direction due to a strong interaction between adjacent atomic moments. This results in a substantial net magnetic dipole moment. Thus, for ferromagnetic materials, $\mu_f \ne 0$.

Considering the above properties:

• Diamagnetic materials have $\mu_d = 0$.
• Paramagnetic materials have $\mu_p \ne 0$.
• Ferromagnetic materials have $\mu_f \ne 0$.

Based on this understanding, the correct option is: $\mu_d=0$ and $\mu_p \ne 0$, which aligns with the inherent magnetic properties of these materials.

Conclusion: The characterizations of magnetic dipole moments for diamagnetic and paramagnetic materials provide the basis for selecting the correct answer.