What can be inferred from an emission spectrum regarding a light source?

An emission spectrum is produced when atoms in a gas or a vapor are excited by energy, such as heat or electrical energy. As these excited atoms return to their lower energy states, they emit light at specific wavelengths corresponding to the differences in energy levels. The fact that this spectrum contains distinct lines at particular wavelengths indicates that the light source emits only certain colors of light, rather than a continuous range. This characteristic is what leads one to infer that the source emits specific wavelengths of light.

For instance, when observing the emission spectrum of hydrogen, we see clearly defined lines that correspond to specific transitions of electrons between energy levels. These lines reveal important information about the composition, temperature, and physical conditions of the gas. The presence of such discrete lines clearly signifies that the source is exciting atoms that are then emitting light at particular wavelengths, confirming that it emits specific wavelengths rather than a broad spectrum.