An electron moving in a circular orbit of radius `r` makes `n` rotation per secound. The magnetic field produced at the centre has magnitude

Options

A. `zero`
B. `(mu_0n^(2)e)/r`
C. `(mu_0n e)/(2r)`
D. `(mu_0n e)/(2pir)`

Answer

C

Explanation

Magnetic field at the center of a circular loop is `B=(mu_0i)/(2r)` but ` i=q/t=e/T=e/(1/n)=ne therefore B=(mu_0 n e)/(2r)`.