Question

Three identical charged balls each of charge $2 C$ are suspended from a common point $P$ by silk threads of $2 m$ each (as shown in figure). They form an equilateral triangle of side $1 m$. The ratio of net force on a charged ball to the force between any two charged balls will be :

• A. $1: 1$
• B. $1: 4$
• C. $\sqrt{3}: 2$
• D. $\sqrt{3}: 1$

Answer 1

Answer: (D)

$F =\frac{ k (2)(2)}{(1)^{2}}$
$( F =$ Force between two charges $)$.
$F =4 k$
$F _{\text {net }}=2 F \cos 30^{\circ}=2 \cdot F \cdot \frac{\sqrt{3}}{2}= F \sqrt{3}$
$\left( F _{\text {net }}=\right.$ Net electrostatic force on one charged ball $)$
$\frac{ F _{\text {net }}}{ F }=\frac{\sqrt{3} F }{ F }=(\sqrt{3})$
Remark: Net force on any one of the ball is zero. But no option given in options.