An electric dipole consists of charges +q and −q separated by a small distance 2d.
Answer the following questions:
a. (i) Derive an expression for the electric potential Vaxial at a point on the axial line of the dipole situated at a distance r(≫d) from its centre.
b. (ii) Obtain a similar expression for the electric potential Vequatorial at a point on the equatorial line at the same distance r.
c. (iii) Using your results, explain why the potential difference between any two points on the same equipotential surface is zero and hence no work is done in moving a charge on such a surface.
d. (iv) Comment on the sign of the potentials obtained in (i) and (ii) and relate it to the orientation of the dipole moment vector p with respect to the position vector of the field point.