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. $\frac{\sqrt{3}q}{4\pi {ϵ}_0{d}^2}$
• B. $\frac{3\sqrt{3}q}{4\pi {ϵ}_0{d}^2}$
• C. $\frac{\sqrt{3}q}{\pi {ϵ}_0{d}^2}$
• D. $\frac{2\sqrt{3}q}{\pi {ϵ}_0{d}^2}$

Answer 1

Answer: (C)

$E_x=\frac{K\left(4q\right)}{R^2}cos30^{\circ }+\frac{K\left(2q\right)}{R^2}cos30^{\circ }+\frac{K\left(2q\right)}{R^2}cos30^{\circ }$