A ring of radius r is uniformly charged with charge q. it is rotated with angular velocity `omega` , then magnetic moment developed in ring is :

Options

A. `(qr^(2) omega)/(2)`
B. `(q omega)/(2 r^(2))`
C. `(q)/(r^(2) omega^(2))`
D. `(2)/(qr^(2) omega)`

Answer

A

Explanation

`M= I. A = q. pi r^(2) . v = q.pi r^(2) * (omega)/(2 pi)`
`:. M = (qr^(2) omega)/( 2)`