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

$A$ uniform magnetic field parallel to the plane of paper existed in space,initially directed from left to right. When a bar of soft iron is placed in the field parallel to it,the lines of force passing through it will be represented by which figure?

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:

What is a magnetic substance? Write its types.

Which of the following is most suitable for the core of electromagnets?

Statement $I :$ The ferromagnetic property depends on temperature. At high temperature,a ferromagnet becomes a paramagnet.
Statement $II :$ At high temperature,the domain wall area of a ferromagnetic substance increases.
In the light of the above statements,choose the most appropriate answer from the options given below :