1. The problem statement, all variables and given/known data An electric dipole moment, vector P, is initially pointing in the directio of a uniform electric field, vector E (say, in the positive x direction). How much external work is needed to turn the dipole by 90 degrees? 2. Relevant equations vector P is directly proportional to E. It will tend to point in the same direction as E. 3. The attempt at a solution The only relevant equation I can gather is the torque N = p X E.