Question

Two similar charges +Q placed at points A & B and - q charge at point C in the midway between A & B in which position - q charge will oscillate

Answer 1

Given:

Two similar charges of magnitude +Q are placed at points A and B. -q charge is placed at point C at midpoint between A and B.

To find:

Direction in which the -q charge will oscillate.

Concept:

The -q charge will oscillate in a direction perpendicular to the line joining the two +Q charges .

For small displacements , the charge q shall perform SHM (Simple Harmonic Motion), which can be proved mathematically.

This is because when the -q charge is displaced in a direction perpendicular to the line AB , it experiences attraction force from the +Q charges and returns back and goes to the opposite direction.

This cycle continues and results in oscillatory motion.

So final answer:

-q will oscillate along CD line (refer to diagram)