Chapter-2|Electrostatic Potential and Capacitance| NCERT 12th Physics:
Any surface which has same electrostatic potential at every point on it is called an equipotential surface.
From above it is clear that V is constant if r is constant.
If all the points at same potential is the electric field are joined, then an equipotential surface is obtained.
The shape of equipotential surface due to a
(I) Line charge is cylindrical.
(II) Point charge is spherical.
Properties of Equipotential Surface:
1. Equipotential surface do not intersect to each other.
2. Equipotential surface are closely spaced in the reason of strong electric field and so on.
3. No work is required to move a test charge on an equipotential surface.
4. Electric field is always normal to the equipotential surface at every point.