Using coulmb's law
[tex]\\ \bull\tt\dashrightarrow F=k\dfrac{q1q2}{r^2}[/tex]
[tex]\\ \bull\tt\dashrightarrow F=8.98\dfrac{2\times 10^{-9}\times 4\times 10^{-9}}{(0.3)^2}[/tex]
[tex]\\ \bull\tt\dashrightarrow F=8.98\dfrac{8\times 10^{-18}C^2}{0.09m^2}[/tex]
[tex]\\ \bull\tt\dashrightarrow F=\dfrac{71.84\times 10^{-18}C^2}{0.09m^2}[/tex]
[tex]\\ \bull\tt\dashrightarrow F=798.2\times 10^{18}Nm^2/C^2[/tex]
[tex]\\ \bull\tt\dashrightarrow F=7.9\times 10^{16}Nm^2/C^2[/tex]
