The magnetic moment of a current $(i)$ carrying circular coil of radius $(r)$ and number of turns $(n)$ varies as

The radius of a circular loop is $r$ and a current $i$ is flowing in it. The equivalent magnetic moment will be

$A$ loop in the form of four connected semi-circular wires carrying current $I$ lies in the $x-y$ plane as shown in the figure. The unit vector $\hat{k}$ is coming out of the plane of the paper. The magnetic moment of the current loop is

Due to the flow of current in a circular loop of radius $R$,the magnetic field produced at the centre of the loop is $B$. The magnetic moment of the loop is

$A$ uniform conducting wire of length $12 a$ and resistance $R$ is wound up as a current-carrying coil in the shape of,
$(i)$ an equilateral triangle of side $a$.
$(ii)$ a square of side $a$.
The magnetic dipole moments of the coil in each case respectively are:

$A$ uniformly charged dielectric ring rotating with constant angular velocity $\omega$ about its geometrical axis produces: