The magnetic moment of a current $(I)$ carrying circular coil of radius '$r$' and number of turns '$n$' depends on

An electron moves in a circular orbit with a uniform speed $v$. It produces a magnetic field $B$ at the centre of the circle. The radius of the circle is proportional to

Magnetic field at the centre of a circular loop of area $A$ is $B$. Then the magnetic moment of the loop is ($\mu_0$ is the permeability of free space).

$A$ current carrying wire of length $L$ is transformed into a coil of $N$ turns. To achieve maximum magnetic moment,the coil

$A$ ring of radius $R$,made of an insulating material,carries a charge $Q$ uniformly distributed on it. If the ring rotates about the axis passing through its centre and normal to the plane of the ring with a constant angular speed $\omega$,then the magnitude of the magnetic moment of the ring is:

Two concentric circular loops of radii $r_{1} = 30 \, cm$ and $r_{2} = 50 \, cm$ are placed in the $X-Y$ plane as shown in the figure. $A$ current $I = 7 \, A$ flows through them in the directions shown. The net magnetic moment of this system of two circular loops is approximately: