The phenomenon of perfect diamagnetism in superconductors is called the . . . . . . .

Name the suitable material for an electromagnet.

The variation of magnetic susceptibility $\left( \chi \right)$ with absolute temperature $T$ for a ferromagnetic material is given in the figure by:

$A$ 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 $\text{ A m}^{-1}$)

The magnetic susceptibility of a paramagnetic material at $-73^{\circ} C$ is $0.0075$. Its value at $-173^{\circ} C$ will be

Curie temperature is the temperature above which