Physics - Modern Physics Question with Solution | TestHub

Magnetic field, $$B=\frac{{\mu }_0}{4\pi }\frac{2\pi i}{r}=\frac{{\mu }_{0}i}{2r}\text{ or }i=\frac{2Br}{{\mu }_0}$$ Also, $A=\pi r^2$ or $r={\left(\frac{A}{\pi }\right)}^{1/2}$ Magnetic moment, $$\begin{array}{rl}M& =iA=\frac{2Br}{{\mu }_0}A\\ & =\frac{2BA}{{\mu }_0}\times {\left(\frac{A}{\pi }\right)}^{1/2}=\frac{2B{A}^{3/2}}{{\mu }_0{\pi }^{1/2}}\end{array}$$