AP Physics 2 / Unit 15: Modern Physics
15.3 Emission and Absorption Spectra
Notes
- Emission spectrum: bright lines from excited atoms emitting photons.
- Absorption spectrum: dark lines where atoms absorbed specific wavelengths.
- Each element has a unique set of lines.
Practice
Dark lines in starlight show:
Photons were absorbed.
Spectral lines can identify elements because:
Like fingerprints.
Bright lines on a dark background are:
Emitted photons.
Ready for more? Take the Unit 15 test.