The magnetic susceptibility of a superconductor is

Options

A. `chi_m=1`
B. `chi_m=-1`
C. `chi_m=0`
D. `chi_m=oo`

Answer

To solve the question regarding the magnetic susceptibility of a superconductor, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Magnetic Susceptibility**:
- Magnetic susceptibility (denoted as χm) is a measure of how much a material will become magnetized in response to an applied magnetic field. It indicates the degree of magnetization of a material when subjected to a magnetic field.

2. **Identify the Nature of Superconductors**:
- Superconductors exhibit a unique property where they can completely expel magnetic fields when cooled below a certain critical temperature. This phenomenon is known as the Meissner effect.

3. **Determine the Type of Magnetism**:
- Superconductors are classified as perfectly diamagnetic materials. This means that they have a very strong negative response to an applied magnetic field.

4. **Quantify the Magnetic Susceptibility**:
- For perfectly diamagnetic materials, the magnetic susceptibility is defined as χm = -1. This indicates that the material completely opposes the applied magnetic field.

5. **Conclusion**:
- Therefore, the magnetic susceptibility of a superconductor is χm = -1.

### Final Answer:
The magnetic susceptibility of a superconductor is -1.

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