The largest wavelength in the ultraviolet region of the hydrogen spectrum is `122` nm. The smallest wavelength in the infrared region of the hydrogen spectrum (to the nearest integer) is

Options

A. `802nm`
B. `823nm`
C. `1882nm`
D. `1648nm`

Answer

B

Explanation

Infrared region Rightarrow paschen series `(n=3)`
`1/lambda=RZ^(2)(1/n_(1)^(2)-1/n_(2)^(2))`
`Rightarrow 1/lambda=(1.1xx10^(7))(1)^(2)(1/3^(2)-1/oo)`
`lambda=9/(1.1xx10^(7))=(900)/(1.1)xx10^(-9)=823nm`