Question

A thin disc of radius R and mass M has charge q uniformly distributed on it. It rotates with angular velocity $\omega$. The ratio of magnetic moment and angular momentum for the disc is?

• A. $\frac{q}{2M}$
• B. $\frac{R}{2M}$
• C. $\frac{q^2}{2M}$
• D. $\frac{2M}{q}$

Answer 1

The correct option is A $\frac{q}{2M}$

$\gamma =\frac{\mu }{L}=\frac{i\ast \pi \ast r^2}{m\ast r^2\ast w}=\frac{q\ast w\ast \pi }{2\pi m}=\frac{q}{2m}$