Answer
$F=2.81 N$
Work Step by Step
Electrostatic force between two charges can be calculated as follows:
$F=K \frac{q_1q_2}{r^2}$
Plugging in the known values, we obtain:
$F=(8.99\times10^9) \frac{(3\times10^{-6})(1.5\times10^{-6})}{(0.12)^2}$
$F=2.81 N$
