We are given the following information
Two charges are identical = q1 = q2 = q
Distance between charges = r = 30 cm = 30/100 = 0.30 m
Force experienced by charges = F = 0.85 N
We are asked to find the charge on each sphere.
Recall that Coulomb’s law is given by
[tex]F=k\frac{q_1q_2}{r^2}[/tex]Where k is the Coulomb constant that is k = 9x10⁹ Nm²/C²
Since the two charges are identical, q1 = q2 = q
[tex]\begin{gathered} F=k\frac{q^2}{r^2} \\ q^2=\frac{F\cdot r^2}{k} \\ q^2=\frac{0.85\cdot0.30^2}{9\times10^9} \\ q^2=8.5\times10^{-12} \\ q=\sqrt{8.5\times10^{-12}} \\ q=2.915\times10^{-6}\; C \end{gathered}[/tex]Therefore, the charge on each sphere is 2.915×10⁻⁶ C
