Answer to Question #100169 in Physics for Angela

Question

Two point charges are separated by a distance r. If the separation n is reduced by a factor of 1.5, by what factor does the electric force between them change?

Answer 1

$$F\sim r^{-2}$$

Thus,

$$\frac{F'}{F}=\frac{r^2}{r'^2}=1.5^2=2.25$$