Question

What is electric dipole moment?

Answer 1

The electric dipole moment for a pair of opposite charges of magnitude $q$ is defined as the magnitude of the charge times the distance $d$ between them. It is a vector quantity and the direction is taken from the negative to the positive charge.
$\overrightarrow{P}=q\overrightarrow{d}$

It is a useful concept in atoms and molecules where the effects of charge separation are measurable, but the distances between the charges are too small to be easily measurable.