If a certain gas is heated and observed through a grating,a bright line spectrum will be seen.If,instead,a source of continuous spectrum shines through a cooler sample of this same gas,a dark absorption spectrum is observed.How do the positions of the lines in these two spectra compare?
A) All of the lines in the spectrum from the hot gas will be at higher frequencies than the corresponding lines in the spectrum of the cooler gas.
B) All of the lines in the spectrum from the hot gas will be at lower frequencies than the corresponding lines in the spectrum of the cooler gas.
C) The lines in the two spectra will be at the same frequencies.They will be the same spectra.
D) These two processes produce spectra by completely different means,and there will be no relationship at all between the two spectra.

Question

Quizplus · Accepted Answer

The lines in both the emission spectrum (from the hot gas) and the absorption spectrum (from the cooler gas) occur at the same frequencies because they are determined by the energy levels of the electrons in the atoms of the gas. When the gas is heated, electrons jump to higher energy levels and emit light of specific frequencies when they fall back down, creating the bright line spectrum. When a continuous spectrum passes through a cooler gas, the gas absorbs light of specific frequencies corresponding to the energy needed for electrons to jump to higher levels, creating dark lines at the same positions.

If a Certain Gas Is Heated and Observed Through a Grating,a