planck's radiation law
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Definition
- Noun:
- (Physics) Planck's radiation law: A fundamental equation in quantum mechanics and thermodynamics that describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature. It marks the birth of quantum theory.
Usage
- Noun:
- Planck's radiation law accurately predicts the intensity of radiation at different wavelengths for a black body.
- The derivation of Planck's radiation law resolved the ultraviolet catastrophe problem in classical physics.
Advanced Usage
- "to derive Planck's radiation law": To mathematically obtain the law from first principles, typically involving quantum statistical mechanics.
- Max Planck originally derived Planck's radiation law by introducing the concept of energy quanta.
- "consistent with Planck's radiation law": Describing experimental data or a theoretical model that agrees with the predictions of the law.
- The cosmic microwave background radiation spectrum is remarkably consistent with Planck's radiation law for a black body at 2.7 Kelvin.
Variants and Related Words
- Planck's law (n): A common abbreviated name for Planck's radiation law.
- Planck's law is a cornerstone of modern physics.
- Black-body radiation (n): The type of electromagnetic radiation described by Planck's radiation law.
- The study of black-body radiation led directly to the formulation of Planck's radiation law.
- Spectral radiance (n): The quantity described by Planck's radiation law.
- Planck's radiation law gives the spectral radiance as a function of wavelength and temperature.
Synonyms
- Planck's law: The most direct synonym.
- Black-body radiation formula: A descriptive synonym emphasizing its application.
Related Phrases
- To obey Planck's radiation law: For a physical system's emission to follow the law's predictions.
- A perfect black body will precisely obey Planck's radiation law.
- The limit of Planck's radiation law: Referring to its behavior in classical (Rayleigh-Jeans) or high-energy (Wien's approximation) limits.
- At long wavelengths, Planck's radiation law reduces to the Rayleigh-Jeans law.
Noun
- (physics) an equation that expresses the distribution of energy in the radiated spectrum of an ideal black body