If `R` is the Rydberg's constant for hydrogen the wave number of the first line in the Lyman series will be

Options

A. `( R)/(2)`
B. `2 R`
C. `( R)/(4)`
D. `(3 R)/(4)`

Answer

D

Explanation

`(1)/(lambda) = R [(1)/(1^(2)) - (1)/(2^(2))]`
or `(1)/(lambda) = ] R [(1) - (1)/(4)] = (3 R)/(36)`
Hence, wavenumber `(1)/(lambda) = (3 R)/(4)`