Question:
Two particles $\mathrm{A}$ and $\mathrm{B}$ having charges $\mathrm{q}$ and $2 \mathrm{q}$ respectively are placed on a smooth table with a separation d. A third particle $\mathrm{C}$ is to be clamped on the table in such a way that the particles $\mathrm{A}$ and $\mathrm{B}$ remain at rest on the table under electrical forces. What should be the charge on $C$ and where should it be clamped?
Solution: