Question
Charge q is uniformly spread on a thin ring of radius R. The ring rotates about its axis with a uniform frequency f Hz. The magnitude of magnetic induction at the centre of the ring is
-
μoqf / 2R
-
μoq / 2fR
-
μoq / 2πfR
-
μoqf / 2πR
Solution
A.
μoqf / 2R
B = μoi / 2R
q = it
⇒ i = q /t = qf
B = μoqf / 2R