Rayleigh–Jeans law at low frequencies

E31549

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.

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AI-generated illustration of Rayleigh–Jeans law at low frequencies

This AI-generated illustration was produced by black-forest-labs/FLUX.2-dev (1024x1024) from a prompt written by openai/gpt-oss-120b from the entity's label + description.

Prompt

Generate an image of the 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.)

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Statements (46)

Predicate Object
instanceOf approximation ⓘ
classical limit of Planck’s law ⓘ
physical law ⓘ
accuratelyDescribes long-wavelength tail of blackbody spectrum ⓘ
appliesTo long wavelengths ⓘ
low frequencies ⓘ
low photon energies ⓘ
associatedWith ultraviolet catastrophe when extrapolated to high frequencies ⓘ
assumes classical electromagnetic field ⓘ
continuous energy spectrum ⓘ
electromagnetic modes have energy kT per degree of freedom ⓘ
context thermodynamic equilibrium of radiation in a cavity ⓘ
contrastWith Wien’s law at high frequencies ⓘ
dependsOn absolute temperature T ⓘ
frequency ν ⓘ
wavelength λ ⓘ
derivedFrom classical statistical mechanics ⓘ
equipartition theorem ⓘ
describes spectral radiance of blackbody radiation ⓘ
domain blackbody radiation ⓘ
failsAt high frequencies ⓘ
short wavelengths ⓘ
field classical electrodynamics ⓘ
statistical physics ⓘ
thermal radiation ⓘ
formulaInFrequencyForm B_ν(T) = (2ν²kT)∕c² ⓘ
formulaInWavelengthForm B_λ(T) = (2ckT)∕λ⁴ ⓘ
historicalRole motivated development of quantum theory ⓘ
implies energy density of radiation grows without bound with frequency in classical theory ⓘ
isApproximationOf Planck’s law of blackbody radiation ⓘ
isClassicalLimitOf Planck’s radiation law ⓘ
isValidInLimit hν ≪ kT ⓘ
λ ≫ hc∕kT ⓘ
namedAfter James Jeans ⓘ
Lord Rayleigh ⓘ
predicts spectral radiance proportional to temperature T ⓘ
spectral radiance proportional to λ⁻⁴ in wavelength domain ⓘ
spectral radiance proportional to ν² in frequency domain ⓘ
relatesQuantity spectral radiance per unit frequency ⓘ
spectral radiance per unit wavelength ⓘ
usedFor approximating cosmic microwave background spectrum at low frequencies ⓘ
usedIn microwave regime analysis ⓘ
radio astronomy ⓘ
usesConstant Boltzmann constant k ⓘ
linked to: Boltzmann constant

speed of light c ⓘ
validFor hν∕kT ≪ 1 ⓘ

How these facts were elicited

Referenced by (3)

Full triples — surface form annotated when it differs from this entity's canonical label.

Planck radiation law → reducesTo → Rayleigh–Jeans law at low frequencies ⓘ
Wien displacement law → relatedTo → Rayleigh–Jeans law ⓘ
linked to: Rayleigh–Jeans law at low frequencies
Lord Rayleigh → knownFor → Rayleigh–Jeans law ⓘ
linked to: Rayleigh–Jeans law at low frequencies