$E_n$ = $\frac{13.12 \times 10^5}{n^2}$ J/mole Energy required to remove the electron completely from n = 5 orbital in an H-atom is = $\frac{13.12 \times 10^5}{5^2}$ J/mole = 0.5248 × $10^5$ J/mole= 5.248 × $10^4$ J/mole = $\frac{5.248 \times 10^4}{6.022 \times 10^{23}}$ = 8.71 × $10^{-20}$ J/atoms Energy required to remove the electron completely from n = 1 orbit in a H-atom is = $\frac{13.12 \times 10^5}{1^2}$ J/mol = 13.12 × $10^5$ J/mol = $\frac{13.12 \times 10^5}{6.022 \times 10^{23}}$ = 2.17 × $10^{-18}$ J/atom ∴ Energy required to remove the electron from n = 1 orbit is 25 times than that required to remove the electron from n = 5.