Equations · equation
Kirchhoff's Law of Thermal Radiation
Radiation · 1859
- Equation
- ε(λ,T) = α(λ,T)
- Field
- Radiation
- Named After
- Gustav Kirchhoff
- Year
- 1859
Symbols
ε emissivity — how well a body radiates at each wavelength · α absorptivity — how well it absorbs the same wavelength · equal for any body in thermal equilibrium
Significance
Good absorbers are good emitters, wavelength by wavelength — a perfect absorber (a 'black body', Kirchhoff's coinage) must radiate a universal spectrum depending on temperature alone. Finding that spectrum's formula became the problem that broke classical physics.
Spectral Types
G-type Stars
Referenced by
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equation
event
theory
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