Substances in which the magnetic moment of a single atom is not zero are known as:

The variation of magnetic susceptibility with the temperature of a ferromagnetic material can be plotted as

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

The magnetic susceptibility of ferromagnetic materials is

$A$ perfectly diamagnetic sphere has a small spherical cavity at its centre, which is filled with a paramagnetic substance. The whole system is placed in a uniform magnetic field $\overrightarrow{B}$. Then the field inside the paramagnetic substance is:

Above the Curie temperature,the susceptibility of a ferromagnetic substance varies