Value of permittivity in free space is

$\text{r}=1\text{m,}\text{F}=\text{1}{\text{N, q}}_1=1{\text{C, q}}_2=1\text{C}$

$\frac{1}{4\pi {\epsilon }_0}=9\times {10}^9\frac{\text{N}-{\text{m}}^2}{{\text{C}}^2}$

${\epsilon }_0=\frac{1}{4\pi \times 9\times {10}^9}$

$=\frac{1\times {10}^{-9}}{4\times 3.14\times 9}$

$=0.008846\times {10}^{-9}$

$=8.85\times {10}^{-12}\frac{{\text{C}}^2}{\text{N}-{\text{m}}^{\text{2}}}$