Three charges +4μC, -2μC and -2μC are fixed at the vertices of an equilateral triangle of side 5mm.

Question

Three charges +4μC, -2μC and -2μC are fixed at the vertices of an equilateral triangle of side 5mm. Net dipole moment of the arrangement is

Professor PC Thomas Classes · Answer

The two negative charges each form a dipole with portions of the positive charge (2μC each). Each dipole has moment $p = qd$. Net dipole moment $= 2 	imes 10^{-8} 	imes \sqrt{3} = 3.46 	imes 10^{-8}$ Cm, considering the 60° angle between dipoles.