Electric charge q, q and −2q are placed at the corners of an equilateral triangle ABC of side L. The magnitude of electric dipole moment of the system is

$(\sqrt{3})$ qL

As shown the three charges are equivalent to two dipoles of magnitude q L.

∴ Equivalent dipole moment

$=\sqrt{(qL)^2+(qL)^2+2(qL)(qL) \cos 60^o}$

= $\sqrt{3} qL$