Electrostatics

Two charges are $+10 \mu \mathrm{C}$ and $-10 \mu \mathrm{C}$ are separated by 10 cm . The magnitude of force acting on another charge $5 \mu \mathrm{C}$ placed at the mid-point of the line joining the two charges will be (use, $\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9$ in SI unit)