Question

Ferromagnetic materials show:

• A. Weak repulsion
• B. Strong attraction
• C. No interaction
• D. Random behaviour

Hint:

Ferromagnetic materials are the only materials that show strong attraction to a magnetic field and can be permanently magnetized.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
This question concerns the fundamental magnetic behavior of ferromagnetic materials when they are introduced into an external magnetic field.

Step 2: Key Formula or Approach:
The magnetic behavior of a material is characterized by its relative magnetic permeability ($\mu_r$) and magnetic susceptibility ($\chi$).
For ferromagnetic materials:
\[ \chi \gg 1 \quad \text{and} \quad \mu_r \gg 1 \] These parameters indicate that ferromagnetic materials have a large and positive response to external magnetic fields.

Step 3: Detailed Explanation:

• Ferromagnetic materials (such as iron, cobalt, and nickel) contain permanent atomic magnetic dipoles.

• In these materials, quantum mechanical exchange interactions cause adjacent dipoles to align parallel to one another within macroscopic regions called magnetic domains.

• When an external magnetic field is applied, these domains readily align with and grow in the direction of the applied field.

• This results in a massive magnetization inside the material that is parallel to the external field, producing a very strong mechanical force of attraction.

• In comparison, diamagnetic materials experience weak repulsion, paramagnetic materials experience weak attraction, and non-magnetic materials show no interaction.

Step 4: Final Answer:
Ferromagnetic materials display a strong attraction to magnetic fields, which corresponds to option (B).