Question

Find the electric dipole moment of the system shown in figure.
​

Answer 1

Now, -2q at the perpendicular base can be arranged as - q and - q.

Intuitively, two dipoles are placed perpendicular to eachother.

We know that, dipole moment terminates at the positive charge.

Dipole Moment is product of magnitude of charge and length of dipole.

Now, Dipole Moment has a direction. In other words, its a vector. Recall vector addition.

Angle between the two vectors is 90° and Length of the dipole is a. Dipole Moment will be aq.

Resultant Dipole Moment will be :

$\sf \: P = \sqrt{(aq) {}^{2} + (aq) {}^{2} + (aq)(aq)cos {90}^{ \circ} } \\ \\ \implies \sf \: P = \sqrt{2(aq) {}^{2}} \\ \\ \implies \boxed{ \boxed{\sf \: P = aq\sqrt{2}}}$