Question

For making an electromagnet the best material to be used is:
A. stainless steel
B. silver.
C. soft iron.
D. nickel.

Answer 1

Hint: An electromagnet is a type of magnet in which magnetic field is produced by an electric current. Electromagnet is usually made up of ferromagnetic materials. The ferromagnetic materials are of two types: soft magnetic materials and hard magnetic materials.

Complete step-by-step answer:
An electromagnetic is a type of magnet in which there is formation of magnetic fields from the current applied in it. In the electromagnets, the moving charges create magnetic fields. Electromagnets usually consist of a large no. of closely spaced turns of the wire.
The core of electromagnets is made up of ferromagnetic materials. They have high permeability and low retentivity.
The ferromagnetic materials are divided into two types:
1. soft magnetic materials: Having low retentivity , low coercivity and low hysteresis loss.
2. hard magnetic materials: having high retentivity, high coercivity, large hysteresis loss.
When a soft rod is placed in a solenoid and current is passed through it. The magnetization is increased by increasing the no. of turns. When we switch off the current in the solenoid, then the I=0 and magnetic field inside the solenoid also comes to zero. Retentivity of soft iron is very low.

The electromagnets are made up of soft iron, which have low retentivity and low coercivity. It has high permeability value (μ). It also allows maximum no. of magnetic field lines to pass through it.
Retentivity of the material is also called residual magnetism and the value of magnetising force is then reduced to zero.
Coercivity is the minimum value of magnetizing intensity(H).
Hence, the best material used to make electromagnet is soft iron.

So, the correct answer is “Option C”.

Note: An electromagnetic is a type of magnet in which there is formation of magnetic fields from the current applied in it. The electromagnets are made up of soft iron, which have low retentivity and low coercivity. A soft rod is placed in a solenoid and current is passed through it. The moving charges in the solenoid produce magnetic fields inside it.