Electric field can be defined as the region of space in which an electrically charged body will be under the influence of an electric force.

An electric field is a vector quantity and can be visualized as arrows going toward or away from charges. The lines are defined as pointing radially outward, away from a positive charge, or radially inward, toward a negative charge.

Coulomb's law of electrostatics states that the force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to square of their distances apart

The mathematical expression is given as:
F = Kq 1 q 2
r²

Where K = 9.0 x 10⁹ Nm²C^-2

Note: Coulomb's law is also an inverse square law hence we can deduce the relationship between F and r as thus:

• If r is increased by a factor of 4, the magnitude of F is the inverse of r² i.e 1/16. In like manner, If F is increased by a factor of 4, the magnitude of r is the square root of F i.e 2
• if r is halved, the magnitude of Force is quadrupled.
• If F is quadrupled, r is halved
• The quarter of F is the double of the radius