Electric Dipole Moment - Torque

Torque

An object with an electric dipole moment is subject to a torque τ when placed in an external electric field. The torque tends to align the dipole with the field, and makes alignment an orientation of lower potential energy than misalignment. For a spatially uniform electric field E, the torque is given by:

where p is the dipole moment, and the symbol "×" refers to the vector cross product. The field vector and the dipole vector define a plane, and the torque is directed normal to that plane with the direction given by the right-hand rule.