A line of an electric field E(r) it is a curve whose tangent vector is just e at every point in space, and it is normal to the equipotential surface everywhere The electric dipole Two charges Q andQ separated by a small distance s in space form an electric dipole. (see Fig 2-6) It generates a potential O Q11 ±丌∈0b±丌∈07a±x∈0 Since + + Ts COS r(1+()2+2cosb) (1+2cosb)1