A collection of hydrogen atoms has been placed into the n = 4 excited state.Which of the following wavelengths of photons will NOT be emitted by the hydrogen atoms as they decay back to the ground state?
A)97 nm
B)490 nm
C)970 nm
D)1900 nm

Question

Quizplus · Accepted Answer

The energy levels of hydrogen are given by the equation E = -13.6/n^2, where n is the principal quantum number. When hydrogen atoms in the n = 4 state decay back to the ground state, they emit photons with wavelengths corresponding to the energy difference between the two levels. The possible energy transitions for n = 4 are: from n = 4 to n = 3 (emitting a photon with a wavelength of 656 nm), from n = 4 to n = 2 (emitting a photon with a wavelength of 486 nm), and from n = 4 to n = 1 (emitting a photon with a wavelength of 121 nm). Therefore, the photon with a wavelength of 970 nm will not be emitted by the hydrogen atoms as it does not correspond to any of the allowed energy transitions.

A Collection of Hydrogen Atoms Has Been Placed into the N