Question

Excitation energy of a hydrogen like ion in its first excitation state is 40.8 eV. Energy needed to remove the electron from the ion in ground state is

• A. 27. 2 eV
• B. 40.8 eV
• C. 13.6 eV
• D. 54.4 eV

Answer 1

The correct option is D

54.4 eV

Energy of hydrogen ion in the ground state = –13.6 eV

$\therefore$ Energy needed to take the electron to the excited state = 40.8 – (–13.6) = 54.4 eV