Definition: Kirchhoff's laws (G.R. Kirchhoff):
- Kirchhoff's first law: An incandescent solid or gas under high pressure will produce a continuous spectrum.
- Kirchhoff's second law: A low-density gas will radiate an emission-line spectrum with an underlying emission continuum.
- Kirchhoff's third law:Continuous radiation viewed through a low-density gas will produce an absorption-line spectrum.