Question

Two identical charge Q each are kept distance r from each other and a third charge q at placed on the line joining the above two charge such that all the three charges in equilibrium what is the magnitude of sign and positive of charge q

Answer 1

Answer:

For charge -q to be in equilibrium, the force acting on '-q' due to +Q at A and +Q at B should be equal and opposite. i.e., the position of the third charge is at x=r/2.