Ratio of longest wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is

Options

A. `3/23`
B. `7/29`
C. `9/31`
D. `5/27`

Answer

D

Explanation

`lambda_"max"=1/(R(1/n_1^2-1/n_2^2))`
For maximum wavelength in Lyman series
`n_1=1` and `n_2=2`
`lambda_"(max)L"=1/(R(1/1-1/4))=4/(3R)`
For maximum wavelength for Balmer series .
`n_1=2 ,n_2=3`
`lambda_((max)_B)=1/(R(1/4-1/9))=36/(5R)`
`lambda_((max)_L)/lambda_((max)_B)=4/(3R)xx(5R)/36=5/27`