Question

Ground state energy of hydrogen atom is -13.6 eV. Then energy of the third excited state is ?

• A. -0.85 eV
• B. -6.8 eV
• C. -1.51 eV
• D. -10.2 eV

Answer 1

The correct option is A -0.85 eV

Third excited means $4th$ normal state i.e $n=4$

in the relation $E_n=E_1/n^2$ where $E_1$ is energy of ground state or $n=1$ state.

So putting $E_1=-13.6eV$ we get the required energy as $E_4=-\frac{13.6eV}{4^2}=-0.85eV$

Option A is correct.