The ratio of te shortest wavelength of two spectral series of hydrogen spectrum is found to be about 9. The spectral series are:

Options

A. Paschen and Pfund
B. Lyman and Paschen
C. Brackett and Pfund
D. Balmer and Brackett

Answer

B

Explanation

Ratio of the spectral lines,
`(1/(lambda_2) = R_H (1/(n_1^2) - 1/(n_2^2))Z^2)/(1/(lambda_1) = R_H (1/(m_1^2) - 1/(m_2^2))Z^2)`
For shortest wavelengths, `n_2 = prop` and `m_2 = prop`
`:. (lambda_1)/(lambda_2) = 9/1 = (m_1^2)/(n_1^2)`
Now, if `m_1 = 3 and n_1 = 1`, the ratio is justified.
Hence, these correspond to Lyman and Paschen series.