solution
In This question we have given ,
Charge on each ball=[tex]q=6.7\times 10^{-9} C[/tex]
force of repulsion between balls is [tex]F=8.2\times 10^{-7}N[/tex]
Let distance between ball be x
We know by Coulombs law,
[tex]F=\frac{k\times q_{1}q_{2}}{x^2}[/tex]..............(1)
here,[tex]k = 9.0\times 10^9 Nm^2C^{-2}[/tex]
Put values of k and charges in equation 1
[tex]8.2\times 10^{-7}N=\frac{9.0\times 10^9 Nm^2C^{-2}\times 6.7^2\times 10^{-18} C^2}{x^2}[/tex]
[tex]8.2\times 10^{-7}N\times x^2=9.0\times 10^9 Nm^2C^{-2}\times 6.7^2\times 10^{-18} C^2}[/tex]
[tex]x^2=\frac{9.0\times 10^9 Nm^2C^{-2}\times 6.7^2\times 10^{-18} C^2}{8.2\times 10^{-7}N}[/tex]
[tex]x=\frac{3\times 6.7}{\sqrt{820} }m[/tex]
[tex]x=.701m[/tex]
therefore distance between two given charges is =.701m
