If the magnetising field on a ferromagnetic material is increased, its permeability is

Options

A. decreased
B. increased
C. is unaffected
D. may be increased or decreased

Answer

To solve the question regarding the relationship between the magnetizing field and the permeability of a ferromagnetic material, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- **Magnetizing Field (H)**: This is the external magnetic field applied to the ferromagnetic material.
- **Magnetic Field (B)**: This is the magnetic field produced inside the ferromagnetic material due to the applied magnetizing field.
- **Permeability (μ)**: This is a measure of how easily a material can become magnetized or how well it can conduct magnetic lines of force.

2. **Formula for Permeability**:
- The permeability (μ) of a ferromagnetic material can be expressed as:
\[ \mu = \frac{B}{H} \]
- Here, B is the magnetic field inside the material, and H is the magnetizing field.

3. **Analyzing the Relationship**:
- From the formula, we can see that permeability (μ) is directly proportional to the magnetic field (B) and inversely proportional to the magnetizing field (H).
- This means that if the magnetizing field (H) increases while the magnetic field (B) does not change significantly, the permeability (μ) will decrease.

4. **Conclusion**:
- Therefore, if the magnetizing field on a ferromagnetic material is increased, its permeability (μ) decreases.

### Final Answer:
The permeability of a ferromagnetic material decreases when the magnetizing field is increased.

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