Calculate potential on the axis of a ring due to charge Q uniformly distributed along the ring of radius R.

Explanation

Let us take Point P to be at a distance x from the centre of the ring as shown in figure. The charge element dq is at a distance x from pont P. therefore, V can be written as
`V=k_(e)int(dq)/(r)=k_(e)int(dq)/(sqrt(x^(2)+a^(2)))`
where, `k_(e)=(1)/(4piepsi_(0))` since each element dq is at the same distance from point P, so we have net potential
`V=(k_(e))/(sqrt(x^(2)+a^(2)))intdq=(k_(e)Q)/(sqrt(x^(2)+a^(2)))`
The net electric potential `V=(1)/(4piepsi_(0))(Q)/(sqrt(x^(2)+a^(2)))`