Two point charges repel each other with a force of 100 N. One of the charges is increased by 10% and other is decreased by 10%. The new force of repulsion at the same distance will be
Answer & explanation
Correct answer: option 3
$F = 100 = \frac{kq^2}{r}$
$F'= \frac{k(1.1q)(0.9q)}{r} = 0.99 \frac{kq^2}{r} = 99 N$