An excited sample of atomic hydrogen emits photons corresponding to three distinct…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
An excited sample of atomic hydrogen emits photons corresponding to three distinct electronic transitions. The measured wavelengths of these photons in vacuum are listed below.
Transition
Wavelength (nm)
X
656.3
Y
486.1
Z
121.6
(a) Calculate the frequency, in Hz, for each of the three emitted photons.
(b) Determine the energy, in J, of a single photon for each transition.
(c) Using your results, compute the ratio EXEZ, where EZ is the energy of a photon from Transition Z and EX is the energy of a photon from Transition X. Express the ratio to three significant figures and interpret its physical meaning.
(d) A sealed discharge tube containing hydrogen is observed to emit 1.25×1018 photons from Transition Y over the course of 10.0 s. Calculate the total energy released in this time interval by those photons, expressing your answer in kilojoules.
(e) Discuss two reasons—one experimental and one theoretical—why Transition Z photons, although far more energetic, might be detected with a lower count rate than Transition X photons in a typical laboratory spectrum.