6.1 Electric field due to a point charge

  Electrostatics

The electrical force $(F)$ between a positive point charge $q$ and test charge $q_0$ at point $P$ which is at a distance $r$ is given by, $$F = \frac{{kq{q_0}}}{{{r^2}}}$$
Then the electric field due to positive point charge $q$ at a distance $r$ is, $$E = \frac{F}{{{q_0}}}$$ or $$E = \frac{{kq}}{{{r^2}}}$$

Note:

• If $q$ is positive, then $\overrightarrow E $ is directed away from $q$.
  
  
  
  
  
  
• If $q$ is negative, then $\overrightarrow E $ is directed towards $q$.