試題詳解

17. A particle with charge q is brought from far away to a point near an electric dipole. No total work is done if the final position of the particle is on:
(A) a line that is perpendicular to the dipole moment.
(B) the line through the charges of the dipole.
(C) a line that makes an angle of 45° with the dipole moment.
(D) none of the above.