Find the longest and shortest wavelengths in the Lyman
series for hydrogen. In what region of the electromagnetic spectrum does each
series lie?

Explanation

The transition equation for Brackett series is given by `(1)/(lambda)=R((1)/(4^(2))-(1)/(n^(2))),n=2,3....`
The largest wavelength is corresponding to n=5
`:. " " (1)/(lambda_("min))=1.097xx10^(7)((1)/(16)-(1)/(25))`
`=0.0246xx10^(7)m`
`:. " " lambda_("max")=40.650xx10^(-7)m=40650Å`
The shortest wavelength corresponds to `n=oo`
`:. " " (1)/(lambda_("min"))=1.097xx10^(7)((1)/(4^(2))-(1)/(oo))`
or `" "lambda_("min") =14.58xx10^(-7) m=14585Å`
Both of these wavelenght lie in infrared region of electromagnetic spectrum .