Apply Coulomb's Law Practice Test

Two point charges are $r = 40,\text{cm}$ apart. Charge 1 is $q_1 = +8.0,\mu\text{C}$ and charge 2 is $q_2 = -2.0,\mu\text{C}$. Using $k = 9.0\times10^9,\text{N·m}^2/\text{C}^2$ and converting to meters, what is the magnitude of the electric force between them?

A charged plastic rod and a small metal sphere are treated as point charges. The rod has $q_1 = +6.0,\mu\text{C}$ and the sphere has $q_2 = -3.0,\mu\text{C}$, separated by $r = 0.20,\text{m}$. Which statement correctly describes the electric force between them?