Q. If 3 charges are placed at the vertices of equilateral triangle of charge $'q'$ each. What is the net potential energy, if the side of equilateral $\mathrm{\Delta}$ is $l\ cm$
A) $\frac{1}{4\pi\varepsilon_{0}}\frac{q^{2}}{l}$
B) $\frac{1}{4\pi\varepsilon_{0}}\frac{{2q}^{2}}{l}$
C) $\frac{1}{4\pi\varepsilon_{0}}\frac{{3q}^{2}}{l}$
D) $\frac{1}{4\pi\varepsilon_{0}}\frac{{4q}^{2}}{l}$
Explanation
(c) $U = \frac{1}{4\pi\varepsilon_{0}}\left\lbrack \frac{Q_{1}Q_{2}}{r_{1}} + \frac{Q_{2}Q_{3}}{r_{2}} + \frac{Q_{1}Q_{3}}{r_{3}} \right\rbrack$
$U_{net} = 3 \times \frac{1}{4\pi\varepsilon_{0}}.\frac{q^{2}}{l}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.