Question

Two charges are found to be 0.25 m apart. The charge of the first is thrice the charge of the second. If the magnitude of the second charge is 2 uC, find the force experienced by the first charge due to the second charge.

Answer 1

Given:

$r=\rm 0.25\: m$

$q_1=3q_2=6*10^{-6}\:\rm C$

$q_2=2*10^{-6}\:\rm C$

The Coulomb's law says

$$F=k\frac{q_1q_2}{r^2}\\ =9*10^9*\frac{6*10^{-6}*1*10^{-6}}{(0.25)^2}=0.864\: \rm N$$