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) Net work done = final PE$-$ initial PE
$= \frac{Qq}{4\pi\varepsilon_{0}l} - \frac{Qq}{4\pi\varepsilon_{0}l} =$ Zero.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.