If the distance between two charges is doubled, the electrostatic force becomes:

Solution

Physics sir · 3 steps

Force goes as one over r squared, so doubling r divides the force by two squared, which is 4.

1. Coulomb's law. The force between two point charges depends on the inverse square of the distance between them.

   F = 1/4πε₀(q₁ q₂)/r²

2. Double the distance. Keep the charges the same and put 2r in place of r. Then F' = 1/4πε₀(q₁ q₂)/(2r)² = F/4.
3. So. The force becomes one-fourth of its earlier value, option (c).

The idea to keep. For any inverse-square force, change the distance by a factor n and the force changes by 1/n². Always square the distance factor before you divide.

Answer from the NTA final answer key. Solution by PrepWiser.