Question

The material that is used to make the core of electromagnets is:
1. Copper
2. Aluminium
3. Soft iron
4. None of these

Answer 1

Correct Answer - Option 3 : Soft iron

CONCEPT:

Electromagnet:

• An electromagnet is a type of magnet in which the magnetic field is produced by an electric current.
• Electromagnets usually consist of wire wounds into a coil.
• The magnetism of the electromagnets can be increased by placing a soft iron rod inside the solenoid.
• The core of electromagnets is made of ferromagnetic materials which have high permeability and low retentivity.
• Electromagnets are used in electric bells, loudspeakers, and telephone diaphragms.
• Giant electromagnets are used in cranes to lift machinery, and bulk quantities of iron and steel.

EXPLANATION:

• The magnetism of the electromagnets can be increased by placing a soft iron rod inside the solenoid.
• When we switch off the solenoid current, the magnetism is effectively switched off since the soft iron core has a low retentivity. Hence, option 3 is correct.