Question

What is the shortest wavelength present in the Paschen series of spectral lines?
A. 720 nm
B. 790 nm
C. 800 nm
D. 820 nm

Answer 1

Correct Answer - D
The wavelength for Paschen series,
`(1)/(lambda)=R[(1)/(3^2)-(1)/(n^2)]`
For shortest wavelength `n=prop`
`therefore (1)/(lambda)=R[(1)/(9)-(1)/(prop^2)]=(R)/(9)rArrlambda=(9)/(R)=(9)/(1.097xx10^7)`
`=8.20xx10^-7m=820nm`.