Question

Three identical charged balls each of charge 2C are suspended from a common point P by silk threads of 2m each (as shown in figure). They form an equilateral triangle of side 1m. 

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) √3 : 2

(D) √3 : 1

Answer 1

Correct option is (D) √3 : 1

(F = Force between two charges).

F = 4k

F_net = 2F cos 30º = 2..F. √3/2 = F√3

(F_net = Net electrostatic force on one charged ball)

F_net/F = √3F/F = (√3)

Remark: Net force on any one of the ball is zero. But no option given in options.