Let electric potential at point P due to small element of length dℓ be dV.
(distance between small element and point P is equal to r)
Electric potential due to whole ring
Electric Potential due to a uniformly charged rod of length L and linear charge density lambda, at a point P on its axial line which is d units away from it
Charge per unit length λ = Q/L
Charge of slice dq = λ.dx
Find the electric potential at the axis of a uniformly charged disc and use potential to find the electric field at same point.
Potential due to ring element of radius r and thickness dr is dv: