A charge `Q` is distributed uniformly on a ring of radius `R` as shown in the following diagrams. Find the electric potential at the center `O` of the ring.
(a)

Explanation

Consider a small charge `dq`. Electric potential at `O` due to `dq`
`dV = (1)/(4 pi in_(0)) . (dq)/(R )`
`V_(O) = Sigma dV = (1)/(4 pi in_(0) R) Sigma dq = (1)/(4 pi in_(0)) .(Q)/(R)`
(b) , (c ) : Answer is same.