Kirchhoff's law of thermal radiation
E93639
Kirchhoff's law of thermal radiation is a fundamental principle in thermodynamics stating that, for a body in thermal equilibrium, its emissivity equals its absorptivity at each wavelength.
All labels observed (4)
| Label | Occurrences |
|---|---|
| Kirchhoff's law of thermal emission | 2 |
| Kirchhoff's law of spectroscopy | 1 |
| Kirchhoff's law of thermal radiation canonical | 1 |
| Kirchhoff’s law of thermal radiation | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T793359 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Kirchhoff's law of thermal radiation Context triple: [Gustav Kirchhoff, notableWork, Kirchhoff's law of thermal radiation]
-
A.
Stefan–Boltzmann law
The Stefan–Boltzmann law is a fundamental principle of thermal radiation stating that the total energy radiated per unit surface area of a black body is proportional to the fourth power of its absolute temperature.
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B.
Planck radiation law
Planck radiation law is a fundamental formula in quantum physics that describes the spectral distribution of electromagnetic radiation emitted by a black body in thermal equilibrium.
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C.
Wien displacement law
Wien's displacement law is a physical law that relates the temperature of a blackbody to the wavelength at which it emits radiation most intensely.
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D.
Fourier's law of heat conduction
Fourier's law of heat conduction is a fundamental physical principle that relates heat flux within a material to the negative gradient of temperature, forming the basis of classical heat transfer theory.
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E.
Rayleigh–Jeans law at low frequencies
The Rayleigh–Jeans law at low frequencies is the classical approximation for blackbody radiation that accurately describes the long-wavelength, low-energy limit of Planck’s radiation spectrum.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Kirchhoff's law of thermal radiation Target entity description: Kirchhoff's law of thermal radiation is a fundamental principle in thermodynamics stating that, for a body in thermal equilibrium, its emissivity equals its absorptivity at each wavelength.
-
A.
Stefan–Boltzmann law
The Stefan–Boltzmann law is a fundamental principle of thermal radiation stating that the total energy radiated per unit surface area of a black body is proportional to the fourth power of its absolute temperature.
-
B.
Planck radiation law
Planck radiation law is a fundamental formula in quantum physics that describes the spectral distribution of electromagnetic radiation emitted by a black body in thermal equilibrium.
-
C.
Wien displacement law
Wien's displacement law is a physical law that relates the temperature of a blackbody to the wavelength at which it emits radiation most intensely.
-
D.
Fourier's law of heat conduction
Fourier's law of heat conduction is a fundamental physical principle that relates heat flux within a material to the negative gradient of temperature, forming the basis of classical heat transfer theory.
-
E.
Rayleigh–Jeans law at low frequencies
The Rayleigh–Jeans law at low frequencies is the classical approximation for blackbody radiation that accurately describes the long-wavelength, low-energy limit of Planck’s radiation spectrum.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
law of thermal radiation
ⓘ
law of thermodynamics ⓘ physical law ⓘ |
| appliedIn |
astrophysics
ⓘ
climate science ⓘ material science ⓘ remote sensing ⓘ thermal engineering ⓘ |
| appliesTo |
bodies in thermal equilibrium
ⓘ
opaque bodies ⓘ partially transparent bodies ⓘ |
| assumes | no net energy exchange at equilibrium ⓘ |
| category | conservation law consequence ⓘ |
| condition |
local thermodynamic equilibrium
ⓘ
thermal equilibrium with surroundings ⓘ |
| consequence |
emissivity cannot exceed absorptivity at a given wavelength in equilibrium
ⓘ
surface color affects both absorption and emission similarly at a given wavelength ⓘ |
| contrastWith | non-equilibrium radiative processes ⓘ |
| coreStatement | For a body in thermal equilibrium, spectral emissivity equals spectral absorptivity at each wavelength. ⓘ |
| dependsOn |
temperature
ⓘ
wavelength ⓘ |
| field |
heat transfer
ⓘ
radiative transfer ⓘ statistical mechanics ⓘ thermodynamics ⓘ |
| hasAlternativeLabel |
Kirchhoff's law of thermal emission
ⓘ
linked to:
Kirchhoff's law of thermal radiation
|
| implies |
good absorbers are good emitters
ⓘ
poor absorbers are poor emitters ⓘ |
| language | English name ⓘ |
| mathematicalForm | ε(λ,T) = α(λ,T) for a body in thermal equilibrium ⓘ |
| namedAfter | Gustav Kirchhoff ⓘ |
| proposedBy | Gustav Kirchhoff ⓘ |
| relatedTo |
Kirchhoff's circuit laws
ⓘ
Kirchhoff's law of thermal emission ⓘ
linked to:
Kirchhoff's law of thermal radiation
|
| relatesConcept |
black-body emissive power
ⓘ
gray body ⓘ radiative equilibrium ⓘ spectral radiance ⓘ |
| relatesQuantity |
absorptivity
ⓘ
emissivity ⓘ |
| scope |
each wavelength separately
ⓘ
spectral quantities ⓘ |
| supports | concept of black body ⓘ |
| symbolDefinition |
α is spectral absorptivity
ⓘ
ε is spectral emissivity ⓘ |
| usedInDerivationOf |
Planck's law of black-body radiation
ⓘ
linked to:
Planck radiation law
Stefan–Boltzmann law ⓘ Wien's displacement law ⓘ
linked to:
Wien displacement law
|
| yearProposed | 1859 ⓘ |
How these facts were elicited
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Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Kirchhoff's law of thermal radiation Description of subject: Kirchhoff's law of thermal radiation is a fundamental principle in thermodynamics stating that, for a body in thermal equilibrium, its emissivity equals its absorptivity at each wavelength.
Referenced by (5)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: Kirchhoff's law of thermal radiation
linked to: Kirchhoff's law of thermal radiation
linked to: Kirchhoff's law of thermal radiation
linked to: Kirchhoff's law of thermal radiation