A wire of length L metre carrying a current of l ampere is bent in the form of circle. Its magnetic moment is

Length of wire, L = $2\mathrm{\pi R}$
Radius of loop, $\mathrm{R}=\frac{\mathrm{L}}{2\mathrm{\pi }}$
Magnetic moment, M = IA

                                       $\begin{array}{l}=I\left(\frac{{\mathrm{\pi L}}^2}{4{\mathrm{\pi }}^2}\right)\\ =\frac{{\mathrm{IL}}^2}{4\mathrm{\pi }}{\mathrm{Am}}^2\end{array}$