• question_answer A system of three charges are placed as shown in the figure : If $D>>d,$the potential energy of the system is best given by:             [JEE Main 9-4-2019 Morning] A) $\frac{1}{4\pi {{\varepsilon }_{0}}}\left[ -\frac{{{q}^{2}}}{d}-\frac{qQd}{2{{D}^{2}}} \right]$   B) $\frac{1}{4\pi {{\varepsilon }_{0}}}\left[ +\frac{{{q}^{2}}}{d}+\frac{qQd}{{{D}^{2}}} \right]$C) $\frac{1}{4\pi {{\varepsilon }_{0}}}\left[ -\frac{{{q}^{2}}}{d}+\frac{2qQd}{{{D}^{2}}} \right]$ D) $\frac{1}{4\pi {{\varepsilon }_{0}}}\left[ -\frac{{{q}^{2}}}{d}-\frac{qQd}{{{D}^{2}}} \right]$

${{U}_{total}}={{U}_{self\,of\,dipole\,}}+{{U}_{\operatorname{int}eraction}}$ $=-\frac{k{{q}^{2}}}{d}-\left( \frac{kQ}{{{D}^{2}}} \right)qd$ $=-k\left[ \frac{{{q}^{2}}}{d}+\frac{qQd}{{{D}^{2}}} \right]$ Option [d]