Question

Two point charges $+q$ and $+q$ are fixed at $(a,0,0)$ and $(-a,0,0)$. A third point charge $-q$ is at origin. State whether its equilibrium is stable, unstable or neutral if it is slightly displaced along $x-$ axis.

• A. Stable
• B. Unstable
• C. Neutral
• D. Data insufficient

Answer 1

The correct option is B Unstable

At $P,$ attraction $F_1>$attraction $F_2$
$\therefore$ Net force is in the direction of displacement. So, equilibrium is unstable.