JEE Main202227 Jun 2022Evening ShiftPhysicsElectrostaticsActual
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
Options
- A3 : 1
- B3 : 2
- C1 : 1
- D1 : 4
Correct answer
A. 3 : 1
Step-by-step solution
We have force between any two charge   F 1 = F 2 = q 2 4 π ε 0 l 2 = F Resultant electrostatics force F R = F 1 2 + F 2 2 + 2 F 1 F 2 cos 60 ° = F 2 + F 2 + 2 F 2 × 1 2 = 3 F 2 So, the ratio of net force on a charged ball to the force between any charged balls is ⇒ F R F = 3