The correct measure of magnetic hardness of a material is

Options

A. remanant magnetism
B. hysterses loss
C. coercivity
D. curie temperature

Answer

To solve the question regarding the correct measure of magnetic hardness of a material, we will analyze the concepts related to magnetic properties and the options provided.

### Step-by-Step Solution:

1. **Understanding Magnetic Hardness**:
- Magnetic hardness refers to a material's ability to retain its magnetization when an external magnetic field is removed. This property is crucial in applications where permanent magnets are needed.

2. **Options Analysis**:
- **Remnant Magnetism**: This is the magnetization left in a material after an external magnetic field is removed. While it is related to how much magnetism a material can retain, it does not directly measure hardness.
- **Hysteresis Loss**: This refers to the energy lost in a magnetic material due to the lag between the magnetization and the applied magnetic field. It is not a measure of hardness but rather a measure of energy loss.
- **Coercivity**: This is defined as the ability of a magnetic material to withstand an external magnetic field without becoming demagnetized. A higher coercivity indicates a harder magnetic material.
- **Curie Temperature**: This is the temperature above which a magnetic material loses its permanent magnetic properties. It does not measure hardness.

3. **Conclusion**:
- Among the options provided, coercivity is the most appropriate measure of magnetic hardness. It indicates how resistant a material is to being demagnetized by an external magnetic field.

### Final Answer:
The correct measure of magnetic hardness of a material is **coercivity**.

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