To determine the force between the charges, we use the equation given above written as:
F = kq1q2 / r^2
where k is a constant, q1 and q2are the charges and r is the distance between the point charges.
F = 9x10^9 (1.602x10^-19) (1.602x10^-19) / 4.5x10^-10^2
F = 1.1406x10^-9 N