$A$ magnet,when placed perpendicular to a uniform magnetic field of strength $10^{-4} \ Wb/m^2$,experiences a maximum torque of $4 \times 10^{-5} \ N \cdot m$. What is its magnetic moment in $A \cdot m^2$?

An iron rod of length $L$ and magnetic moment $M$ is bent in the form of a semicircle. Now its magnetic moment will be

Two magnetic poles have a pole strength of $0.01 \, A \cdot m$ each and are separated by a distance of $0.1 \, m$. What is the magnetic field at the midpoint between the two poles?

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 . . . . . . $N$.

The name 'magnet' came from which island?

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.