Electromagnets are made of soft iron because soft iron has

Options

A. high retentivity and high coercive force
B. high retentivity and low coercive force
C. high retentivity and high coercive force
D. low retentivity and low coercive force.

Answer

### Step-by-Step Solution:

1. **Definition of Electromagnets**:
- Electromagnets are magnets that generate a magnetic field when an electric current passes through them. They are temporary magnets, meaning they only exhibit magnetic properties when current flows.

2. **Properties of Soft Iron**:
- Soft iron is a material that is commonly used to make electromagnets. The key properties that make it suitable are:
- **Low Retentivity**: This means that soft iron does not retain significant magnetization once the external magnetic field (or current) is removed. This allows for quick demagnetization.
- **Low Coercivity**: This refers to the material's ability to resist being demagnetized. Soft iron has low coercivity, meaning it can be easily magnetized and demagnetized.

3. **Magnetic Domains**:
- Soft iron contains magnetic domains that can be easily aligned in the presence of an external magnetic field (when current flows). When the current is turned off, these domains can quickly return to a disordered state, losing their magnetization.

4. **Hysteresis Loop**:
- The hysteresis loop for soft iron is narrow, indicating low energy loss during magnetization and demagnetization. This is a graphical representation of the relationship between magnetic intensity and magnetization.

5. **Conclusion**:
- Due to its low retentivity and low coercivity, soft iron is ideal for use in electromagnets. It allows for efficient magnetization and demagnetization, making it practical for applications where the magnetic field needs to be turned on and off frequently.

### Final Answer:
Electromagnets are made of soft iron because soft iron has **low retentivity and low coercivity**.

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