Physics - Magnetism Question with Solution | TestHub

Given, $r=0.05\mathrm{nm}=0.05\times 10^{-9}\mathrm{m}$ $$\begin{array}{l}\left(\because 1\mathrm{nm}=10^{-9}\mathrm{m}\right)\\ n=10^{16}\text{ revolutions }\\ e=1.6\times 10^{-19}\mathrm{C}\end{array}$$ We know that The magnetic moment $M=AL$ $$\begin{array}{rl}M& =\pi r^2\times ne\\ M& =3.14\times {\left(0.05\times 10^{-9}\right)}^2\times 10^{16}\times 1.6\times 10^{-19}\\ M& =0.1256\times 10^{-18}\times 10^{16}\times 10^{-19}\\ \text{or }M& =1.26\times 10^{-23}{\mathrm{Am}}^2\end{array}$$