Question
The electric field E due to a point charge at any point near it is defined as $\text{E} = \DeclareMathOperator*{\median}{\text{lim}} \median_{\text{q}\rightarrow0}\frac{\text{F}}{\text{q}}$ where q is the test charge and F is the force acting on it. What is the physical significance of $\DeclareMathOperator*{\median}{\text{lim}} \median_{\text{q}\rightarrow0}$ in this expression? Draw the electric field lines of a point charge Q when (a) Q>0 and (b) Q<0.
