The radius of the second Bohr orbit for hydrogen atom is :

The radius of the second Bohr orbit for hydrogen atom is :

(Plank's const. $\mathrm{h}=6.6262 \times 10^{-34} \mathrm{Js}$; mass of electron $=9.1091 \times 10^{-31} \mathrm{~kg}$; charge of electron $\mathrm{e}=$ $1.60210 \times 10^{-19} \mathrm{C}$; permittivity of vaccum

$\left.\epsilon_{0}=8.854185 \times 10^{-12} \mathrm{~kg}^{-1} \mathrm{~m}^{-3} \mathrm{~A}^{2}\right)$