試題詳解

14. In electrostatic equilibrium, the electric field just outside any charged con- ductor is
(A) always zero；
(B) always perpendicular to the surface of the conductor；
(C)always parallel to the surface of the conductor, along the gra- dient of the surface charge distribution；
(D) always parallel to the surface, but perpendicular to the gradient of the surface charge distribution,
(E) of no particular direction.