Question

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. $\frac{1}{4\pi {ϵ}_0}\frac{Qq}{l}$
• B. $\frac{1}{4\pi {ϵ}_0}\frac{Qq}{l^2}$
• C. $\frac{1}{4\pi {ϵ}_0}Qql$
• D. Zero

Answer 1

The correct option is D Zero

According to figure, potential at A and C are equal. Hence work done in moving – q charge from A to C is zero.