A sodium vapor lamp, commonly used in street lighting, emits a prominent yellow spectral line with a wavelength of 589 nm589\text{ nm}589 nm.
Calculate, in eV\text{eV}eV, the magnitude of the change in the energy level of the sodium atom that is responsible for the emission of a photon of this wavelength.
Explain, with reference to the physical processes within the atom, the difference between how this emission line is produced compared to an absorption line of the same wavelength.
