Question

If we keep a bar magnet instead of soft iron in the solenoid then what will happen?

Will it's magnetic property will increase ?

Or It will act as an electromagnet?

Answer 1

Yes. The use of soft iron rod as core in a solenoid produces the strongest magnetism. The magnetic field around an electromagnet is just the same as the one around a bar magnet. It can, however, be reversed by turning the battery around.
Unlike bar magnets, which are permanent magnets, the magnetism of electromagnets using a soft iron, can be turned on and off just by closing or opening the switch.