The unit of pole strength of a magnet is:

$A$ bar magnet having centre $O$ has a length of $4 \ cm$. Point $P_1$ is in the broad side-on (equatorial) position and $P_2$ is in the end side-on (axial) position with $OP_1 = OP_2 = 10 \ m$. The ratio of magnetic intensities $H$ at $P_1$ and $P_2$ is:

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.

$A$ sample of a ferromagnetic iron in the shape of a cube of side $1.0 \mu m$ contains $8.7 \times 10^{28}$ atoms per cubic metre and the magnetic dipole moment of each iron atom is $9.3 \times 10^{-24} A m^2$. Then the maximum possible magnetic dipole moment (in $A m^2$) of the sample is nearly

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

The magnetic lines of force inside a bar magnet