For a hydrogen atom, the ratio of the largest wavelength of Lyman series to that of the Balmer series is.

For a hydrogen atom, the ratio of the largest wavelength of Lyman series to that of the Balmer series is.
  1. $5: 36$
  2. $5: 27$
  3. $3: 4$
  4. $27: 5$

Solution

$\mathrm {Lyman}$

$\frac{1}{\lambda_1}=\mathrm{R}\left[\frac{1}{1}-\frac{1}{4}\right]=\frac{3 \mathrm{R}}{4}$
$\lambda_1=\frac{4}{3 R}$ ________...(1)
and $\mathrm {Balmer}$
$\frac{1}{\lambda_2}=\mathrm{R}\left[\frac{1}{4}-\frac{1}{9}\right]=\frac{5 \mathrm{R}}{36}$
$\lambda_2=\frac{36}{5 R}$
Then, $\frac{\lambda_1}{\lambda_2}=\frac{5}{27}$

Asked in: JEE Main 2025 (07 Apr Shift 1)

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