The relation $H \propto I$ and the susceptibility $\chi = \frac{I}{H}$ are not applicable for which of the following substances?

One of the following substances having the tendency to move from a stronger region to a weaker region of the magnetic field is:

Assertion $(A)$: Electromagnets are made of soft iron.
Reason $(R)$: Coercivity is small for soft iron.

In some ferromagnetic materials,magnetization disappears on the removal of the external magnetic field. Such materials are called:

The following plots show Magnetization $(M)$ vs Magnetising field $(H)$ and Magnetic susceptibility $(\chi)$ vs temperature $(T)$ graphs:
Which of the following combinations will be represented by a diamagnetic material?

$A$ sample of a paramagnetic salt containing $3 \times 10^{24}$ atomic dipoles each of dipole moment $2 \times 10^{-23} \text{ A-m}^2$ is subjected to a uniform magnetic field of $880 \text{ mT}$ and cooled to a temperature of $3.5 \text{ K}$. The degree of magnetic saturation achieved is $10 \%$. If the sample is subjected to a magnetic field of $990 \text{ mT}$ and cooled to a temperature of $2.1 \text{ K}$, then the total dipole moment of the sample is (in $\text{ A-m}^2$)