Magnetic hysteresis is exhibited by magnetic materials which are

The intensity of magnetisation $I$ is plotted against the magnetising field $H$ for different substances. The curves $A$ and $B$ shown in the adjoining figure are associated with

The coercivity of a small magnet is $4 \times 10^3 \ A/m$. It is placed inside a solenoid of length $1 \ m$ having $500$ turns to demagnetize it. The current that must be passed through the solenoid is .......... $A$.

The coercivity of a magnet,where the ferromagnet gets completely demagnetized,is $3 \times 10^{3} \text{ A m}^{-1}$. The minimum current required to be passed in a solenoid having $1000 \text{ turns m}^{-1}$,so that the magnet gets completely demagnetized when placed inside the solenoid,is:

Which of the following statements is incorrect about hysteresis?

The coercivity of a magnet is $5 \times 10^3 \text{ A/m}$. The amount of current required to be passed in a solenoid of length $30 \text{ cm}$ and the number of turns $150$,so that the magnet gets demagnetized when placed inside the solenoid is ............. $A$.