Target Exam

CUET

Subject

Physics

Chapter

Atoms

Question:

Energy required for the electron excitation in $Li^{2+}$ from the first to the third Bohr orbit is

Options:

36.3 eV

108.8 eV

122.4 eV

12.1 eV

Correct Answer:

108.8 eV

Explanation:

$\Delta E = 13.6 z^2 (\frac{1}{n^2} - \frac{1}{m^2})$

$\Delta E = 13.6 3^2 (\frac{1}{1^2} - \frac{1}{3^2}) = -13.6 \times 9 (1 - \frac{1}{9}) = 13.6 \times 8 = 108.8 J$