Question

A charge $Q$ is to be divided into two parts such the force between them is maximum. They should be divided as

• A. $\frac{Q}{4},\frac{3Q}{4}$
• B. $\frac{Q}{3},\frac{2Q}{3}$
• C. $\frac{Q}{8},\frac{7Q}{8}$
• D. $\frac{Q}{2},\frac{Q}{2}$

Answer 1

The correct option is D $\frac{Q}{2},\frac{Q}{2}$

$\begin{array}{c}poseoneobjectreceivesacheqandtheotherQ-q.Theforcebetweentheobjectis\\ F=\frac{kq\left(Q-q\right)}{d^2}\\ For,Ftobemax\frac{dF}{dq}=0\\ Q-2q=0\\ q=\frac{Q}{2}\end{array}$

Hence, the option $D$ is the correct answer.