Domain formation is the necessary feature of

What is a ferromagnetic substance? What is a magnetic domain?

The variation of magnetic susceptibility $(\chi)$ with magnetising field $(H)$ for a paramagnetic substance is represented by which of the following graphs?

Given below are two statements:
Statement $I:$ For a diamagnetic substance $-1 \leq \chi < 0$,where $\chi$ is the magnetic susceptibility.
Statement $II:$ Diamagnetic substances,when placed in an external non-uniform magnetic field,tend to move from the stronger to the weaker part of the field.
In the light of the above statements,choose the correct answer from the options given below.

The variation of magnetic susceptibility $(\chi )$ with temperature for a diamagnetic substance is best represented by:

If $\chi_1$,$\chi_2$,and $\chi_3$ are the magnetic susceptibilities of a paramagnetic material at temperatures $T_1 \ K$,$T_2 \ K$,and $T_3 \ K$ respectively,then which of the following relations is correct?