The electric field due to a point charge at distance ‘r’ is 

The electric field at a distance 'r' due to a point charge is given by:

\(\bar E= \frac{Q}{{4\pi {\epsilon_0}{r^2}}} \hat a_r\)

r = distance from the point charge

â_r = unit direction vector

This is explained with the help of the following diagram:

As the distance from the point charge decreases the magnitude also decreases.

Important Points:

• The direction is radial: outward for +|Q| and inward for -|Q|
• Magnitude: Constant on any spherical shell
• Flux through any shell enclosing Q is the same: E_AA_A = E_BA_B