Energy of the electron in $n^{\text {th }}$ orbit of hydrogen atom is given by $E_n=-\frac{13.6}{n^2}$ eV. The amount of energy needed to transfer electron from first orbit to third orbit is
Answer & explanation
Correct answer: option 3
For n = 1, $E_1=-\frac{13.6}{(1)^2}$ = -13.6 eV
and for n = 3, $E_3=-\frac{13.6}{(3)^2}$ = -1.51 eV
So required energy is
$E_3-E_1=-1.51-(-13.6)$ = 12.09 eV