Question

a force of 500N exist between two identical points charge separate by a distance of 40cm.calculate the magnitude of the two point charge with solution.

Answer 1

Force

$F=\frac{kq_1q_2}{r^2}$

$q_1=q_2=q$

$F=\frac{kq^2}{r^2}$

$q=\sqrt\frac{Fr^2}{k}$

$q=\sqrt\frac{500\times0.16}{9\times10^9}=94.28\times10^{-6}C$

$q_1=q_2=94.28\mu C$