question_answer 22)

Figure shows a charge array known as an electric quadrupole. For a point on the axis of the quadrupole, obtain the dependence of potential on r for  and contrast your results with that due to an electric dipole, and an electric monopole (i.e., a single charge.)                

Answer:

(i) For large distance, r, the potential                                                 i.e. of  type.                 (ii) Due to electric dipole, the potential is of 1/r2 type.                 (iii) Due to an electric monopole, the potential is of 1/r type.