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]

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