In layman's term: like charges don't attract while opposite charges doelectrostatic forces between point A( which is charged) and point B (which is also charged) are proportional to the charge of point A and point B. there is also something else about this law that I don't quite remember.
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Here is the formula:
F = k x Q1 x Q2/d^2
What the formula means:
F=force between charges
Q1 and Q2= amount of charge
d=distance between these two charges
k= Coulombs constant (proportionally constant)
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I think that about covers it and hopefully this helped.