Kirchhoff's Laws (Kirchhoff's Three Laws Of Spectroscopy)
indicate the source of Spectral Lines.
- A hot solid, liquid, or dense gas produces a Continuous Spectrum.
- A hot thin gas produces Emission Lines.
- A continuous spectrum passing through a cold thin gas produces Absorption Lines.
The developer, physicist Gustav Kirchhoff, also devised other groups of laws,
e.g., "Kirchhoff's Laws" of circuits.