JEE Main 2019 Physics question
A thin ring of 10 cm radius carries a uniformly distributed charge. The ring rotates at a constant angular speed of 40π rad s about its axis, perpendicular to its plane. If the magnetic field at its centre is T, then the charge carried by the ring is close to ( N/A).
Answer: (D)
Solution
I = q(20 Hz); ⇒ C.