Electric Field due to a Circular Ring of Charge—

Let us consider a circular ring of radius ‘a’ and total charge q is distributed over it.

            Let P be a point at a distance r from the centre of the ring and at the axis of ring, where electric field due to ring is to be determined.

We have two components of ,

1. dE Cosà along the axis
2. dE Sinà perpendicular to axis

Now, consider the second element which is diametrically opposite to the first element and again on resolving electric field, the component which are perpendicular to axis will cancelled outeach other and the component along the axis will add on.