$A$ circular coil and a square coil are prepared from two identical metal wires,and the same current is passed through them. The ratio of the magnetic dipole moment associated with the circular coil to that of the square coil is:

An electron in a circular orbit of radius $0.05 \,nm$ performs $10^{16}$ revolutions per second. What is the magnetic moment due to the rotation of the electron? $(e = 1.6 \times 10^{-19} \,C)$

$A$ circular coil of $1000$ turns and area of cross-section $1.5 \times 10^{-4} \, m^2$ is carrying a current of $2 \, A$. What is the magnetic moment associated with the coil in $Am^2$?

$A$ 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:

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

$A$ wire carrying current $I$ is bent in the shape $A, B, C, D, E, F, A$ as shown,where rectangle $A, B, C, D, A$ and $A, D, E, F, A$ are perpendicular to each other. If the sides of the rectangles are of lengths $a$ and $b$,then the magnitude and direction of the magnetic moment of the loop $A, B, C, D, E, F, A$ is