List of top Physics Questions on Electrostatic potential asked in AIEEE

Three charges $-q_1, +q_2$ and $-q_3$ are placed as shown in the figure. The x-component of the force on $-q_1$ is proportional to

The work done in placing a charge of $8 ??10^{-18}$ coulomb on a condenser of capacity 100 micro-farad is