Question

Electrons of energy $10.20eV$ and $12.09eV$ can cause radiations to be emitted from $H-$atom. What is the principal quantum number of the orbit to which an electron in the hydrogen atom is raised in each case ?

• A. n = 1,5
• B. n = 1,6
• C. n = 2,3
• D. n = 5,6

Answer 1

Answer: (C)

n = 2,3

$\Delta E=-13.6(\frac{1}{n_2^2}-\frac{1}{n_1^2})eV$
For the radiation having energy 10.20eV
$10.20=-13.6(\frac{1}{n_2^2}-\frac{1}{1^2})$
Hence, $n_2=2$
For the radiation having energy 12.09eV
$12.09=-13.6(\frac{1}{n_2^2}-\frac{1}{1^2})$
Hence, $n_2=3$