1. The problem statement, all variables and given/known data A dipole, consisting of a charge -q at position vector r and a charge +q at position vector r+s, is sitting in an external electric field E(ext). (a) Write down the total force on the dipole F(dipole) due to the external field (b) Show that when s is small, F(dipole) approx. = (dot product of p and del operator)*E(ext) where p is the electric dipole moment, p = q s (c) In what limit does the result become exact? 2. Relevant equations p = q s F = torque = cross product (p and E(ext)) 3. The attempt at a solution (a) F(dipole) = cross product (p and E(ext)) = q* cross product (s and E(ext)) stuck on (b) and (c) Please help!