The emission lines of a given atom occur at the exact same energies as that atom's absorption lines.

Question

Quizplus · Accepted Answer

This statement is known as the "principle of spectral reciprocity" and is true for all elements. It means that if an atom absorbs a photon of a certain energy, it will also emit a photon of that same energy when transitioning back to a lower energy state. This is why the spectra of elements can be used to identify them, since each element has a unique set of absorption and emission lines.

The Emission Lines of a Given Atom Occur at the Exact