Hysteresis

The soft-iron is a suitable material for making an electromagnet. This is because soft-iron has

Hysteresis loops for two magnetic materials A and B are given below :

These materials are used to make magnets for electric generators, transformer core and electromagnet core. Then it is proper to use :

The coercivity of a small magnet where the ferromagnet gets demagnetized is $3\times10^3$ A m$^{-1}$. The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetized when inside the solenoid, is :