Question

Three charges are placed as shown in figure if the electric potential energy of system is zero, then $Q:9$

• A. $\frac{Q}{q}=\frac{-2}{1}$
• B. $\frac{Q}{q}=\frac{2}{1}$
• C. $\frac{Q}{q}=\frac{-1}{2}$
• D. $\frac{Q}{q}=\frac{1}{4}$

Answer 1

The correct option is D $\frac{Q}{q}=\frac{1}{4}$

$\begin{array}{c}\frac{-KQq}{r}\times 2+\frac{k{q}^2}{2r}=0\\ \Rightarrow \frac{2kQq}{r}=\frac{k{q}^2}{2r}\\ \frac{Q}{q}=\frac{1}{4}\end{array}$

$\therefore$ Option $D$ is correct .