A short electric dipole has a dipole moment $15\times {10}^{-8} \mathrm{C}-\mathrm{m}$. A point charge of 10 $\mathrm{\mu C}$ is placed at a distance of 10 cm on the dipole axis from the centre of the dipole. Then potential energy stored on the charge-dipole system is 

Potential at the point due to the dipole, $\mathrm{V}=\frac{1}{4\mathrm{\pi }{\in }_0}\frac{\mathrm{p}}{{\mathrm{r}}^2}=\frac{9\times {10}^9\times 15\times {10}^{-8}}{{(0.1)}^2} \mathrm{volt}$

                                                                                      $\text{=135}\times {\text{10}}^3\text{ volt}$

$\therefore$ Electro static potential energy stored in the system $=\mathrm{VQ}=135\times {10}^3\times 10\times {10}^{-6} \mathrm{J}=1.35\mathrm{J}$