Practice portal › Electric Charge and Properties › Electric Charge and Coulomb's Law

The force acting between two point charges kept at a certain distance is F. Now the magnitudes of the charges are doubled and the distance between them is halved. The force acting between them is ……

Asked in RS Academy GUJCET booklet · Coulomb's law and superposition

Answer: (4) 16F

Step-by-step solution

Given: F = (kq₁q₂)/(r²); new charges 2q₁ and 2q₂; new distance r/2.

Idea: the Coulomb force is proportional to the product of the charges and to 1/(r²).

F' = (k(2q₁)(2q₂))/((r/2)²) = (4kq₁q₂)/((r²)/4)

F' = 16 (kq₁q₂)/(r²) = 16F

So the new force is 16F.

Why the other options are wrong

More Electric Charge and Coulomb's Law questionsAll Electric Charge and Coulomb's Law questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer