The unit magnetic dipole moment is .

The ratio of the magnetic field at the centre of a current-carrying circular coil to magnetic moment is $x$. If the current and the radius both are doubled. The new ratio will become

A wire carrying current $\mathrm{I}$ is bent in the shape$\mathrm{ABCDEFA}$ as shown, where rectangle $\mathrm{ABCDA}$ and $\mathrm{ADEFA}$ are perpendicular to each other. If the sides of the rectangles are of lengths $\mathrm{a}$ and $\mathrm{b}$, then the magnitude and direction of magnetic moment of the loop $\mathrm{ABCDEFA}$ is :

A $100$ turn closely wound circular coil of radius $10 \mathrm{cm}$ carries a current of $3.2 \mathrm{A}$.

$\left(\mathrm{b}\right)$ What is the magnetic moment of this coil?

Two concentric circular loops of radii $r_1=30 \mathrm{cm}$ and $r_2=50 \mathrm{cm}$ are placed in $X-Y$ plane as shown in the figure. A current $I=7 \mathrm{A}$ is flowing through them in the direction as shown in figure. The net magnetic moment of this system of two circular loops is approximately

A uniform conducting wire of length $12a$ 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: