From Columb's Law which describe the electrostatic interaction.
The formula is given and looks as follows [tex]F=k \frac{|q1*q2|}{r^{2} } [/tex]
where:
F is force acting between charges,
q1 - charge one given in columbs,
q2 - charge two given in columbs,
r - distance between charge in meters
k - constant
First, we have to convert out formula to get r.
[tex]F=k \frac{q1*q2}{r^{2} } [/tex]
Now we multiplaty by [tex]r^{2} [/tex] both sides of equation
[tex]F* r^{2} =k*|q1*q2|[/tex]
Now we devide both sides by F
[tex] r^{2} =k \frac{|q1*q2|}{F} [/tex]
Next step is take square root
[tex]r= \sqrt{k \frac{|q1*q2|}{F}} [/tex]
We have all date, we can subsitute it to our formula
[tex]r= \sqrt{k* \frac{|q1q2"}{F} } = \sqrt[2]{8.9* 10^{9* \frac{0.001*0.001}{200} }} = 6.67 [m][/tex]
