Question

What will be the nature of equipotential surfaces due to a point charge, situated at infinity?

(a) Plane surface

(b) Spherical

(c) Elliptical

(d) Cylindrical

This question was posed to me in homework.

Origin of the question is Equipotential Surfaces in chapter Electrostatic Potential and Capacitance of Physics – Class 12

Answer 1

Right answer is (a) Plane surface

To explain: If a point charge is situated at infinity, the electric field lines coming out of it will be in the form of parallel straight lines. As we know that field lines cut the equipotential surfaces orthogonally, therefore the equipotential surfaces must be plane surfaces. They can be considered the surface of a sphere of infinite radius.