Question

An electron moving in a circular orbit of radius r makes n rotations per second. The magnetic field produced at the centre has magnitude ____________.

Options

• `(mu_0 "ne")/(2pir)`

• zero

• `(mu_0 "n"^ 2 "e")/ r`

• `(mu _0 "ne")/ (2r)`

Answer 1

An electron moving in a circular orbit of radius r makes n rotations per second. The magnetic field produced at the centre has magnitude `(mu_0"ne")/ (2r)`.

Explanation:

B = `(mu_0 I)/ (2r)`

I = `q/t` = e × n

B = `(mu_0  "e" xx "n")/ (2r)`