Work Step by Step
Electric field lines point from high potential to low potential. The E field points from B toward A, so the electric potential at B is higher than at A. The E field points from A toward C, so the electric potential at C is lower than at A. Points A and D are on an equipotential line – it takes no work to move a charge north or south, perpendicular to the electric field. The electric potential at D is the same as it is at A.