Electric potential due to dielectric dipole on equatonal line at distance r from the centre of the dipole is (P = dipole moment) (assume dipole as very short).

\(V=\pm \frac{1}{4 \pi \varepsilon_0} \frac{P}{r^2} \) \(V=\pm \frac{1}{4 \pi \varepsilon_0} \frac{2 P}{r^2} \) \(V = \pm \frac{1}{4 \pi \varepsilon_0} \frac{P}{r^3} \) V = 0

V = 0

Potential due to two charges {q and -q} cancel each other. Hence Potential V = 0