The ratio of magnetisation I to the magnetic field intensity H is

Options

A. Permeability
B. Magnetic intensity
C. Diamagnetics
D. Magnetic susceptibility

Answer

To solve the question regarding the ratio of magnetization \( I \) to the magnetic field intensity \( H \), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Magnetization and Magnetic Field Intensity**:
- Magnetization \( I \) (often denoted as \( M \)) is a measure of the magnetic moment per unit volume of a material.
- Magnetic field intensity \( H \) is a measure of the strength of the magnetic field produced by an external source.

2. **Defining Magnetic Susceptibility**:
- Magnetic susceptibility \( \chi \) is a dimensionless proportionality constant that indicates how much a material will become magnetized in an applied magnetic field.
- The formula for magnetic susceptibility is given by:
\[ \chi = \frac{I}{H} \]
- Here, \( I \) is the magnetization, and \( H \) is the magnetic field intensity.

3. **Finding the Ratio**:
- From the definition of magnetic susceptibility, we can directly express the ratio of magnetization \( I \) to magnetic field intensity \( H \):
\[ \frac{I}{H} = \chi \]
- Therefore, the ratio of magnetization to magnetic field intensity is equal to the magnetic susceptibility.

4. **Conclusion**:
- The answer to the question is that the ratio of magnetization \( I \) to the magnetic field intensity \( H \) is the magnetic susceptibility \( \chi \).

### Final Answer:
The ratio of magnetization \( I \) to the magnetic field intensity \( H \) is given by:
\[ \frac{I}{H} = \chi \quad \text{(Magnetic Susceptibility)} \]