Q. An electron moving in a circular orbit of radius $r$ makes $n$ rotations per second. The magnetic field produced at the centre has a magnitude of
A) $\frac{\mu_{0}ne}{2r}$
B) $\frac{\mu_{0}n^{2}e}{2r}$
C) $\frac{\mu_{0}ne}{2\pi r}$
D) Zero
Explanation
(a) Corresponding current $i = en$
So $B = \frac{\mu_{0}}{4\pi}.\frac{2\pi(en)}{r} = \frac{\mu_{0}ne}{2r}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.