The product of the magnitude of the charge and the distance between the centres of positive and negative charge is called

Concept:

• Electric field strength is a measure of the electric field intensity at a point due to a charge. It is the amount of electric force produced per unit charge.
  • Electric field strength (E) at a point due to a point charge q is given by the formula

Where r is the distance from the point charge to the point at which E is determined.

• Electric dipole a couple formed from two equal opposite charges q and –q, which are separated by a distance 2r.

Explanation:

• When two equal and opposite charges are placed at a very small distance to each other then this arrangement is called an electric dipole. 
• The electric dipole moment is defined as the product of the magnitude of one charge and the distance between the charges in an electric dipole.

⇒ P = q × 2r    

Where 2r = distance between the two charges