Identify the paramagnetic substance.

$A$ paramagnetic sample shows a net magnetization of $0.8 \text{ A m}^{-1}$ when placed in an external magnetic field of strength $0.8 \text{ T}$ at a temperature of $5 \text{ K}$. If the temperature is raised to $20 \text{ K}$, then the magnetization becomes: (in $\text{ A m}^{-1}$)

Which of the following statements are true about the magnetic susceptibility ${\chi _m}$ of a paramagnetic substance?

Which of the following statements is true in respect of diamagnetic substances?

Which one of the following characteristics is not associated with a ferromagnetic material?

The magnetic susceptibility of a paramagnetic substance at $-173^{\circ} C$ is $1.5 \times 10^{-2}$. To have the susceptibility $0.5 \times 10^{-2}$,the change in temperature in ${ }^{\circ} C$ is