Physics - Current Electricity Question with Solution | TestHub

Potential at $P$ due to $(+q)$ charge of dipole $$V_1=\frac{1}{4\pi {\epsilon }_0}\cdot \frac{q}{(z-a)}$$ Potential at $P$ due to $(-q)$ charge of dipole $V_2=\frac{1}{4\pi {\epsilon }_0}\cdot \frac{-q}{(z+a)}$
Total potential at $P$ due to electric dipole $$\begin{array}{rl}V& =V_1+V_2\\ & =\frac{1}{4\pi {\epsilon }_0}\cdot \frac{q}{(z-a)}-\frac{1}{4\pi {\epsilon }_0}\frac{q}{(z+a)}\\ & =\frac{q}{4\pi {\epsilon }_0}\frac{(z+a-z+a)}{(z-a)(z+a)}\\ \text{ or }V& =\frac{2qa}{4\pi {\epsilon }_0\left(z^2-a^2\right)}\end{array}$$