Answer:
![Q = 21.09 * 10^(-8) C](https://img.qammunity.org/2022/formulas/physics/high-school/erc709zxu9cgb6myc9s8pw1f6ovpdh3w6c.png)
Step-by-step explanation:
We know from theory that the magnitude of the force between two charges is measured by the expression
![F=\frac1{4\pi\epsilon} (Qq)/(r^2)](https://img.qammunity.org/2022/formulas/physics/high-school/tyhd61vovosy3qya1hvs939bvcknsvfqqh.png)
We know that two spheres have the same charge, and let's assume they're in a vacuum, so
![\epsilon = \epsilon_0 =8.85*10^(-12) C^2/Nm^2](https://img.qammunity.org/2022/formulas/physics/high-school/8bw799jifa5p86zw08mpzynp80r00vbok4.png)
At this point we can solve for Q
![Q^2 = 4\pi\epsilon F r^2 = 4\pi * (8.85 * 10^-12)* (6* 10^-3) * (2 * 10^-1)^2 = 444.624 * 10^(-17) = 4446.24* 10^-16 C^2 \rightarrow Q = 21.09 * 10^(-8) C](https://img.qammunity.org/2022/formulas/physics/high-school/im8z4pew22gdvf34czo1pbfrwgtf03d4ht.png)
Double check calculations for safety, as usual