Question

A charge(-q) and another charge(+Q) are kept at two points A and B respectively, keeping the charges (+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. $\frac{1}{4\pi {\epsilon }_0}\frac{Qq}{l}$
  
• B. $\frac{1}{4\pi {\epsilon }_0}\frac{Qq}{l^2}$
  
• C. $\frac{1}{4\pi {\epsilon }_0}.Qql$
• D. $zero$

Answer 1

The correct option is D $zero$

Net work done = Final PE – Initial PE
$=-\frac{Qq}{4\pi {\epsilon }_{0}l}-\frac{-Qq}{4\pi {\epsilon }_{0}l}=0$