Question

An electron moves in a circular orbit with a uniform speed v. It produces a magnetic field B at the centre of the circle. The radius of the circle is proportional to a) root over B/v b) B/v c) root over v/B d)v/B

Answer 1

The electric current corresponds to the revolution of electron,

I = e * v / 2 * pie * r

The magnetic field due to circular current at the center

B = (μ0 / 4* π) * (2 * π * i) / r = (μ0 / 4π) * (e * v / r^2) Þ

R = square root (μ0 / 4π) * (e * v / B) Þ r ∝ square root (v / B)

Answer 2

Answer: (a) (V/B)*1/2

Explanation: for explanation see the image below