Electromagnets are made of soft iron because soft iron has:

Question

Accepted Answer

1. **Function of Electromagnets:** Electromagnets are temporary magnets that must behave as magnets only when a current flows through the solenoid and lose their magnetism immediately when the current is switched off.
2. **Properties Required:**
   - **Low Retentivity:** The material should retain minimum magnetism when the magnetising field is removed. If retentivity is high, the core would act like a permanent magnet even after the current stops.
   - **Low Coercivity:** The material should be easily demagnetised. It should require a very small (or zero) reverse field to wipe out the residual magnetism. This also implies low hysteresis loss, which is crucial for efficiency.
   - **High Permeability:** It should be easily magnetised to a strong value by the current.
3. **Soft Iron vs. Steel:** Soft iron is a ferromagnetic material with **low retentivity**, **low coercivity**, and high permeability. In contrast, steel (used for permanent magnets) has high retentivity and high coercivity .
4. **Conclusion:** Soft iron is selected for electromagnets because of its low retentivity and low coercive force.

Step-by-Step Solution

Practice All PHYSICS Questions