$A$ thin rod of length $L$ has magnetic moment $M$ when magnetised. If the rod is bent into a semicircular arc,what is the magnetic moment in the new shape?

The force between two identical bar magnets whose centres are $r \ m$ apart is $4.8 \ N$,when their axes are in the same line. If the separation is increased to $2r$,the force between them is reduced to . . . . . . $N$.

In the following figures,the lines of magnetic induction due to a magnet $SN$ are given by:

$A$ magnetized wire of magnetic moment $M$ and length $L$ is bent into an arc of a circle subtending an angle of $60^{\circ}$ at the center. The new magnetic moment is:

$A$ bar magnet $AB$ is cut into two equal parts as shown in the figure. One part is kept over the other so that the pole $C_{2}$ is above $C_{1}$. If $M$ is the magnetic moment of the original magnet,the magnetic moment of the combination so formed is

$A$ bar magnet of magnetic moment $M$ is placed at right angles to a magnetic induction $B$. If a force $F$ is experienced by each pole of the magnet,the length of the magnet will be