A beam of light having wavelength distributed uniformly between 450 nm to 550 nm passes through a sample of hydrogen gas. Which wavelength will have the least intensity in the transmitted beam?
487 nm
ΔEmax=hc450=2.76eV
ΔEmin=hcλ=2.25eV
The absorption of energy by the H2 atom which lies exactly between these two is 2.55 eV from n=2 to n=4, hence wavelength which has been absorbed by hydrogen is λ=hc2.25=487 nm