Question

Change 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

Answer 1

Explanation:

We know that,

current = charge/time --------(i)

we also know that the angular velocity(w) = 2 Pi / t

t = 2 pi / w

Put this value in eq. (i)

I = qw / 2pi -------(ii)

The formula for magnetic field is:

B = U• I / 2R

Put the value of I from (ii) in the formula of B, we get

B = U• qw / 4 pi R