What is true of equipotential surface? (a) The PD between any two points on the surface is zero (b) The electric field is always perpendicular to the surface (c) Equipotential surface are always spherical (d) No work is done in moving a charge along the surface

All are correct (a), (b), (c) (a), (b), (d) (b), (c), (d)

(a), (b), (d)