The magnetic property of a magnetic substance is associated with

The variation of intensity of magnetisation $(I)$ and the applied magnetic field intensity $(H)$ for three magnetic materials $X$,$Y$ and $Z$ are shown in the graph as $OX$,$OY$ and $OZ$ respectively. The materials $X$,$Y$ and $Z$ respectively are:

$A$ sample of paramagnetic salt contains $2 \times 10^{24}$ atomic dipoles each of dipole moment $1.5 \times 10^{-23} \text{ J T}^{-1}$. The sample is placed under a homogeneous magnetic field of $0.6 \text{ T}$ and cooled to a temperature of $4.2 \text{ K}$. The degree of magnetic saturation achieved is $20 \%$. What is the total dipole moment of the sample for a magnetic field of $0.9 \text{ T}$ and a temperature of $2.8 \text{ K}$ (in $\text{ J T}^{-1}$)?

The variation of magnetic susceptibility $(\chi)$ with absolute temperature $(T)$ for a ferromagnetic material is:

What is the nature of the magnetic susceptibility of a diamagnetic substance?

$A$ paramagnetic material has $10^{28} \text{ atoms/m}^3$. Its magnetic susceptibility at temperature $350 \text{ K}$ is $2.8 \times 10^{-4}$. Its susceptibility at $300 \text{ K}$ is