Question

Total energy of an electron in the ground state of hydrogen atom is $-13.6eV$. Its total energy, when hydrogen atom is in the first excited state, is:

• A. $+13.6eV$
• B. $+3.4eV$
• C. $-3.4eV$
• D. $-54.4eV$

Answer 1

The correct option is C $-3.4eV$

Total energy in the first excited state :

$=\frac{-13.6}{n^2}eV$

(where $n=2$)

$=\frac{-13.6}{2^2}=\frac{-13.6}{4}=-3.4eV$.