Question

The electrostatic force between two charges is originally F. Which expression represents the new electrostatic force between the two charges if one charge doubles and the other one is divided by three?
• 1/6
• 3/2
• 2/3
• 6

Answer 1

Answer: c)• 2/3

Explanation:

Lets say q1 and q2 are two charges with r distance far apart.

So electrostatic force

F = (k q1 q2) / r²

as k = Coulomb's constant

Now

q1' = 2q1

q2' = q2/3

Therefore the new electrostatic force

F' = (k q'1 q'2) / r²

F' = (k 2q1 q2) / 3r²

F' = 2/3 [(k q1 q2) / r²]

so F' = 2/3F

New electrostatic force  is 2/3F