Question

The force between two objects, each of charge +Q is measured as +F when the objects are separated a distance d apart. If the charge on each object is doubled, determine the new force between them:

Answer 1

Answer:

$F'=4F$

Explanation:

According to Coulomb's law, the magnitude of the force (F) between two  objects  with the same charge(+Q), separated a distance (d) apart, is defined as:

$F=\frac{kQ^2}{d^2}$

Here k is the Coulomb constant. The charge on each object is doubled, that is $Q'=2Q$:

$F'=\frac{kQ'^2}{d^2}\\F'=\frac{k(2Q)^2}{d^2}\\F'=4\frac{kQ^2}{d^2}\\F'=4F$