Physics - Electrostatics Question with Solution | TestHub

The magnitude of force on $A$ due to $B$ and on $B$ due to $A$ is same but both will act in opposite directions as the electrostatic force between them is repulsive.
$\therefore {\overrightarrow{\mathrm{F}}}_{\mathrm{AB}}=-{\overrightarrow{\mathrm{F}}}_{\mathrm{BA}}$