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

If a piece of metal is thought to be a magnet,which one of the following observations would offer conclusive evidence?

What is the pole strength of a bar magnet? Express the magnetic dipole moment in terms of pole strength.

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.

The magnetism of a magnet is due to

$A$ steel wire of length $l$ and magnetic moment $M$ is bent into a semicircular arc of radius $R$. The new magnetic moment is