A charge is distributed uniformly over a ring of radius 'a'. Obtain an expression for the electric intensity E at a point on the axis of the ring. Hence show that for points at large distances from the ring, it behaves like a point charge

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Suppose that the ring is placed with its plane perpendicular to the x-axis, as shown in the above i figure. Consider a small element dl of the ring. So the charge dq on the element dl is