Q. A charge $( - q)$ and another charge $( + Q)$ are kept at two points $A$ and $B$ respectively. Keeping the charge $( + Q)$ fixed at $B,$ the charge $( - q)$ at $A$ is moved to another point $C$ such that $ABC$ forms an equilateral triangle of side $l.$ The net work done in moving the charge $(–q)$ is
A) $\frac{1}{4\pi\varepsilon_{0}}\frac{Qq}{l}$
B) $\frac{1}{4\pi\varepsilon_{0}}\frac{Qq}{l^{2}}$
C) $\frac{1}{4\pi\varepsilon_{0}}Qql$
D) Zero
Explanation
(d) According to figure, potential at $A$ and $C$ are equal. Hence work done in moving $- q$ charge from $A$ to $C$ is zero
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.