Two point charges, initially 2 cm apart, are moved to a distance of 10 cm apart.

Question

By what factor does the resulting electric force between them change?

a. 5 b. (1/5) c. (1/25)

Answer 1

From the Coulomb's Law

F  ∝1/d^2

F2/F1=d1^2/d2^2

F2/F1=2^2/10^2

          =4/100

          =1/25

Therefore, the option (c) is the correct.