An electric dipole of dipole moment is 6 . 0 × 10 - 6 C m placed in a uniform electric field of 1 . 5 × 10 3 N C - 1 in such a way that dipole moment is along electric field. The work done in rotating dipole by 180 ° in this field will be_______ mJ .

Step-by-step solution

The work done for rotating a dipole is given by the change in the potential energy. The potential energy is given by U = - p → · E → W   = ∆ U   =   U f − U i So, the work done is W = - p E cos 180 ° - ( - p E cos 0 ° ) = 2 p E = 2 × 6 × 10 - 6 × 1 . 5 × 10 3 = 18   mJ