Question

The minimum energy required to excite $H_2$ atom from its ground state is

• A. 3.4 eV
• B. 13.6 eV
• C. 12.1 eV
• D. 10.2 eV

Answer 1

Answer: (D)

10.2 eV

Answer 2

Energy of hydrogen atom in ground state, $E_1 = \frac{-13.6}{1^2} = - 13.6 \, eV$
Energy of hydrogen atom in first excited state, $E_2 = \frac{-13.6}{2^2} = - 3.4 \, eV$
$\therefore$ Minimum energy required = $E_2 - E_1$
\hspace50mm = -3.4 eV - (-13.6 eV )
\hspace50mm =+ 10.2eV