$A$ bar magnet having magnetic moment $M$ is bent as an arc. Its magnetic moment

The resultant magnetic moment of three magnetic dipoles,each of magnetic moment $M$,shown in the arrangement is:

$A$ bar magnet having pole strength $q_m$ and magnetic moment $m$ is divided into two equal parts along its length. The new pole strength is . . . . . . and the magnetic moment is . . . . . . respectively.

Verify Ampere's law for the magnetic field of a point dipole with dipole moment $\vec{M} = M\hat{k}$. Take $C$ as the closed curve running clockwise along the $x$-axis from $x = R$ to $x = a$,then along a circular arc of radius $r$ in the $xz$-plane from $\theta = 0$ to $\theta = \pi$,and finally back to the starting point.

What causes the couple acting on the needle of a compass?

$A$ steel wire has a magnetic moment $M$. What will be its magnetic moment if it is bent into a semi-circular arc?