Question

A negatively charged particle is placed exactly midway between two fixed particles having equal positive charge. What will happen to the charge (a) if it is displaced at right angle to the line joining the positive charges? (b) if it is displaced along the line joining the positive charges?

Answer 1

In first case if the displacement is small it will perform SHM or will come back to initial position.
In second case the force of positive charge near to it will predominate and it will move towards it