Question

A circular coil of closely wound $N$ turns and radius $r$ carries a current $I$. Write the expression for the following:
(i) the magnetic field at its centre
(ii) the magnetic moment of this coil

Answer 1

(i) : Magnetic field at the center $B=\frac{{\mu }_{o}IN}{2r}$

(ii) : Area of the coil $A=\pi r^2$

$\therefore$ Magnetic moment of the coil $\mu =INA=\pi r^{2}IN$