Two identical electric dipoles are arranged parallel to each other with separation between them large compared to the length of individual dipole. The electrostatic energy of interaction of the two dipoles in this position is U. (a) Find work done in slowly rotating one of the dipoles by `90^(@)` so as to bring it to position shown in Fig. (b). (b) Find work done in rotating one of the dipoles by `180^(@)` so as to bring it to the position shown in Fig. (c). `O_1` and `O_2` are centers of the dipoles.

Answer

(a). `-(KP^(2))/(r^(3))`
(b) `-(2KP^(2))/(r^(3))`