Question

Derive the expression for the electric potential due to an electric dipole at a point on its axial line.

Answer 1

Let P be an axial point at distance r from the center of the dipole. Electric potential at point P is given as

V = V₁​ + V_2​

V₁​ and  V₂ ​are the potentials at point P due to charges +q and –q respectively

Hence, the electric potential is \(\frac 1{4\pi \varepsilon_0} \left(\frac {2P}{(r^2 - 4a^2)}\right)\).

Answer 2

Consider a dipole (±q) having length (2l). Let a point P be at a distance of r from the centre of dipole.

The potential at P due to +q