Question

The ferromagnetic core of electromagnets should have

• A. A broad hysteresis loop
• B. High permeability and high retentivity
• C. Low permeability and low retentivity
• D. Low permeability and high retentivity
• E. High permeability and low retentivity

Answer 1

The correct option is E High permeability and low retentivity

An electromagnet must possess following property :

1. The material should have low retentivity so that it gets demagnetised easily

2. For the electromagnet to be very strong, it should have a high value of saturation magnetisation

3. It should have low coercivity

4. Hysteresis loss should be small. It should not be heated up during magnetisation and demagnetisation

5. High premeability