In the hysteresis curve,the value of magnetic induction $(B)$ which remains in a substance when the value of the magnetizing force $(H)$ is made zero $(H=0)$ is called

The study of the hysteresis curve for a given material is used to estimate the:

$A$ metal rod is subjected to cycles of magnetisation at the rate of $42 \ Hz$. The density of the metal is $6 \times 10^3 \ kg \ m^{-3}$ and its specific heat capacity is $0.1 \times 10^3 \ cal \ kg^{-1} \ ^{\circ}C^{-1}$. If the area of its $B-H$ loop corresponds to an energy density of $10^{-2} \ J \ m^{-3}$,then the rise in its temperature in one minute is: (in $^{\circ} C$)

Magnetic hysteresis is exhibited by . . . . . . magnetic materials.

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 ............. $A$.

$A$ bar magnet has a coercivity of $4 \times 10^3 \, A \, m^{-1}$. It is desired to demagnetize it by inserting it inside a solenoid $12 \, cm$ long and having $60$ turns. The current that should be sent through the solenoid is . . . . . . $A$.