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_(0) n e)/(4pi r)`
C. `(mu_(0) n e)/(2 r)`
D. `(mu_(0) n^(2) e)/(2 r)`

Answer

C

Explanation

`omega = 2 pi n rad//sec`
`i = (q)/(T) = (e)/(2pi//omega) = e n`
`B = (mu_(0)i)/(2R) = (mu_(0)n e)/(2r)`