electric charges

Identify that these constitute two electric dipoles, with charge q and separating distance of l, and placed so that their negative charged coincide or sit at one corner of the equilateral triangle and other ends i.e. positive charges are separated by same distance l.

In other words, two electric dipoles, each of magnitude, p = ql, are placed at an angle 60° between them.

Hence the net electric dipole, is a vector sum of the two, and magnitude of the resultant dipole is,

(p²+p²+2ppcos60) = 3p = 3ql.

Regards,

Team,

TopperLearning.