The following figure shows the variation of intensity of magnetisation versus the applied magnetic field intensity, $H$, for two magnetic materials $A$ and $B$:

Identify the materials $A$ and $B$

The following figure shows the variation of intensity of magnetisation versus the applied magnetic field intensity, $H$, for two magnetic materials $A$ and $B$:

Draw the variation of susceptibility with temperature for $B$.

Figure below shows a small magnetized needle $A$ placed at a point $O$. The arrow shows the direction of its magnetic moment. The other arrows show different positions (and orientations of the magnetic moment) of another identical magnetized needle $B$.

(a) In which configurations is the system not in equilibrium?

Figure below shows a small magnetized needle $A$ placed at a point $O$. The arrow shows the direction of its magnetic moment. The other arrows show different positions (and orientations of the magnetic moment) of another identical magnetized needle $B$.

In which configuration is the system in stable equilibrium.