what is a soft iron core? how can it make an electromagnet stronger?

Hi Dishajain!

Soft iron core is a piece (or pieces) of soft iron used as the core of electromagnets, inductors and transformers. The soft iron core makes the magnetic field very strong compared to the air core. This is due to the high permeability of the soft iron. That is, soft iron can be easily magnetized to a high level with a small magnetic field.

Cheers!!