Question

The electron energy in hydrogen atom is given by $E=-\frac{21.7\times {10}^{-12}}{n^2}erg$. Calculate the energy required to remove an electron completely from n=2 orbit. What is the longest wavelength (in cm) of light that be used to cause this transition?

Answer 1

Energy required to remove electron completely from $n=2$ orbit

$E=\frac{-21.7\times {10}^{-12}}{2^2}$erg

$=-5.425\times {10}^{-12}$erg

$\frac{hc}{\lambda }=-5.425\times {10}^{-12}$

$\frac{{10}^7\times 6.626\times {10}^{-34}\times 3\times {10}^8\times {10}^2}{\lambda }=5.425\times {10}^{-12}$

$\lambda =\frac{6.626\times {10}^{-27}\times 3\times {10}^{10}}{5.425\times {10}^{-12}}$

$=3.664\times {10}^{-5}cm$

$=366.40nm$