What is meant by dipole moment?

Question

wy it is acting from -q to +q

Answer 1

The moment is the effect of the di-pole (two opposite charges) at a distance.

As the distance or the angle to the charges changes, so does the effect.

+q

-----------------------------------  r

-q  

The dipole moment vector is directed from minus charge and towards positive charge.  This is a convention and is consistent with measurements.

There is a good explanation, with diagrams, at http://www.av8n.com/physics/electric-dip...

There are real life applications.  Dipole antennas are common in radio communication.

Field strength at any one point is the result of dipole moment.