Question

Calculate the force between two charges each of $20milli$ coulomb separated by a distance of $20cm.$ in air.

Answer 1

Force = $\frac{k{q}_1{q}_2}{r^2}$

$=\frac{9\times {10}^9\times 20\times {10}^{-3}\times 20\times {10}^{-3}}{(20\times {10}^{-2}{)}^2}$

$=\frac{36\times {10}^5}{4\times {10}^{-2}}$

$=9\times {10}^{7}N$