State the purpose of soft iron core used in making an electromagnet

The purpose of using a soft iron core in making an electromagnet is twofold:

1. Enhancement of Magnetic Field: Soft iron is a ferromagnetic material, which means it can be magnetized easily. When the electric current passes through the coil wrapped around the soft iron core, the magnetic field produced by the current is greatly amplified by the soft iron. This results in a much stronger electromagnet.

2. Easy Magnetization and Demagnetization: Soft iron has a high magnetic permeability and low retentivity. This means it can be magnetized and demagnetized very quickly. When the electric current is switched on, the soft iron core becomes strongly magnetized. When the current is switched off, it loses its magnetism almost instantly. This property is very useful in devices like electric bells and relays, where the electromagnet needs to be switched on and off rapidly.