Find the shortest and longest wavelengths in the Lyman series of hydrogen atom.
Q.22 Find the shortest and longest wavelengths in the Lyman series of hydrogen atom.
Q.22 Find the shortest and longest wavelengths in the Lyman series of hydrogen atom.
Best answer
Answer: Shortest \(\approx 911.6\) Å; longest \(\approx 1215\) Å.
For the Lyman series, \(\dfrac{1}{\lambda} = R_H\left(\dfrac{1}{1^2} - \dfrac{1}{n^2}\right)\), \(n = 2, 3, 4, \dots\)
Shortest wavelength (series limit, \(n = \infty\)):
\[\frac{1}{\lambda_s} = R_H \Rightarrow \lambda_s = \frac{1}{1.097\times10^{7}} = 9.116\times10^{-8}\ \text{m} = 911.6\ \text{Å}\]Longest wavelength (\(n = 2\)):
\[\frac{1}{\lambda_l} = R_H\left(1 - \frac{1}{4}\right) = \frac{3R_H}{4} \Rightarrow \lambda_l = \frac{4}{3\times1.097\times10^{7}} = 1.215\times10^{-7}\ \text{m} = 1215\ \text{Å}\]Log in or create a free account to answer this question.