The ultimate individual unit of magnetism in any magnet is called

The unit of pole strength of a magnet is:

The length of a steel wire is $L$ and its magnetic moment is $M$. On bending it into the shape of a semicircle,its magnetic moment will be

If two identical bar magnets, each of length $l$, pole strength $m$ and magnetic moment $M$ are placed perpendicular to each other with their unlike poles in contact, the magnetic moment of the combination is

$A$ bar magnet of magnetic moment $M$ is cut into two parts of equal length. The magnetic moment of each part will be ......... $M$.

Use:
$(i)$ the Ampere's law for $\vec{H}$ and
$(ii)$ continuity of lines of $\vec{B}$,to conclude that inside a bar magnet,
$(a)$ lines of $\vec{H}$ run from the $N$ pole to $S$ pole,while
$(b)$ lines of $\vec{B}$ must run from the $S$ pole to $N$ pole.