Question

What is not 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 is always spherical
(D) No work is done in moving a charge along the surface

Answer 1

Hint: The surface which has the same potential on all the points on the surface is generally called an equipotential surface. There is no work required to move one charge from one point to another point on the equipotential surface. Any surface with the same electric potential at each point is known as an equipotential surface.

Complete step by step solution
The equipotential surface is any surface in which the potential value is constant in any point on that surface. In other terms, the potential difference between any two points in an equipotential surface is equal to zero. The electric field is always perpendicular to the surface because in the equipotential surface there is no potential difference along any direction which is parallel to the equipotential surface. So, the electric field is not parallel to the surface. For a uniform electric field, the equipotential surface planes are normal to the surface.

The two equipotential surface lines can never be intersecting. If suppose the two equipotential surfaces intersect, then the point of intersection of the two electric potentials is not possible. The equipotential surface will have any shape. For the isolated charge, the equipotential surface is a sphere. But the equipotential surface is not always a sphere.

Hence, the option (C) is the answer

Note: The equipotential surface will have the potential difference as zero, then the work done in any point of the equipotential surface is equal to zero. The direction of the equipotential surface is from high potential to the low potential.