Question

The value of the energy for the first excited state of hydrogen atom will be

• A. -13.6eV
• B. -3.40eV
• C. -1.51eV
• D. -0.85eV

Answer 1

The correct option is B

-3.40eV

From the Bohr's postulates, we know
the total energy of the $n^{th}$ orbit,

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

$E_2$ = $-\frac{13.6}{2^2}$ [Because first excited state will be $2^{nd}$ orbit]

$E_2$ = $-\frac{13.6}{4}$ = $-3.4eV$