Question

An electron of charge $e$ and mass $m$ is moving in a circular loop of radius $r$ with a uniform angular speed $\omega$. Then which of the following statements are correct?

• A. The equivalent current flowing in the circular path is proportional to $r^2$
• B. The magnetic moment due to circular current loop is independent of $m$
• C. The magnetic moment due to circular loop is equal to $2e/m$ times the angular momentum of the electron
• D. The angular momentum of the particle is proportional to the areal velocity of electron

Answer 1

Answer: (B), (D)

The correct options are
B The magnetic moment due to circular current loop is independent of $m$
D The angular momentum of the particle is proportional to the areal velocity of electron

Magnetic moment $m=IA$
$=\frac{ev}{2\pi r}\times \pi r^2=\frac{evr}{2}$
Angular momentum $=2m\frac{dA}{dt}$