Question

why is soft iron used as a core of the electromagnet used in electric bell ?

Answer 1

The soft iron inside the coil makes the magnetic field stronger because it becomes a magnet itself when the current is flowing. Soft iron is used because it loses its magnetism as soon as the current stops flowing. Soft iron is said to form a temporary magnet.

Answer 2

Because soft iron quickly gains the magnetism and make electromagnet
More powerful and it quickly looses the magnetism when current I turned off as compared to other materials