Question

An electric field on a plane is described by its potential V = 20(r^-1 + r^-2), where r is the distance from the source. The field is due to

(a) A monopole

(b) A dipole

(c) Both a monopole and a dipole

(d) A quadruple

I got this question in an interview.

My enquiry is from Advanced and Tricky Questions topic in section Advanced and Tricky Questions of Electromagnetic Theory

Answer 1

The correct answer is (c) Both a monopole and a dipole

To explain I would say: In the potential given, one component is inversely proportional to r, which is due to a monopole and the other component is inversely proportional to r^2, which is due to a dipole.