Question

The magnetic moment of an electron (charge = -e, mass = m) moving in a circular orbit of radius r with speed v about a nucleus of mass M is proportional to

• A. mr
• B. vr
• C. evr
• D. Mvr

Answer 1

The correct option is C evr

Since magnetic moment in general is equal to i X A where i is the current and A is area.

In this case current flowing will be e v/ 2$\pi$r

hence magnetic moment = (ev/2$\pi$r ) x $\pi$$r^2$