Question

Three charged particles $A, B$ and $C$ with charges $- 4q, 2q$ and $- 2q$ are present on the circumference of a circle of radius d. The charged particles $A, C$ and centre $O$ of the circle formed an equilateral triangle as shown in figure. Electric field at $O$ along $x$-direction is :

• A. $\frac{\sqrt{3}q}{4\pi\epsilon_{0}d^{2}}$
• B. $\frac{3\sqrt{3}q}{4\pi\epsilon_{0}d^{2}}$
• C. $\frac{\sqrt{3}q}{\pi\epsilon_{0}d^{2}}$
• D. $\frac{2\sqrt{3}q}{\pi\epsilon_{0}d^{2}}$

Answer 1

Answer: (C)

$E_{x}=\frac{K\left(4q\right)}{R^{2}}cos\,30^{\circ}+\frac{K\left(2q\right)}{R^{2}}cos\,30^{\circ }+\frac{K\left(2q\right)}{R^{2}}cos\,30^{\circ }$