Question

When a soft iron core is introduced in a coil, the strength of the magnetic field:

Answer 1

When a soft iron core is introduced, the strength of the magnetic field increases. In the given figure, the field due to the coil with the iron core will be greater than the field due to the coil if the iron core were not present.
When we switch on the current, the coil becomes an electromagnet. But also, the soft iron core becomes a magnet. It will add to the strength of the electromagnet.