$A$ circular coil of area $2 \,cm^2$ has $1000$ turns. If the current through the coil is $1 \,A$, then its magnetic moment is (in $\,Am^2$)

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

$A$ charged particle going around in a circle can be considered to be a current loop. $A$ particle of mass $m$ carrying charge $q$ is moving in a plane with speed $v$ under the influence of magnetic field $\overrightarrow{ B }$. The magnetic moment of this moving particle is:

Derive an expression for the torque acting on a current-carrying loop suspended in a uniform magnetic field.

In a hydrogen atom,the electron is making $6.6 \times 10^{15} \text{ rev } s^{-1}$ around the nucleus in an orbit of radius $0.528 \text{ Å}$. The magnetic moment in $\text{A-m}^2$ is:

Two wires of the same length are shaped into a square and a circle. If they carry the same current,the ratio of their magnetic moments is: