blackbody radiation
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Definition
- Noun:
- The electromagnetic radiation emitted by an ideal blackbody: This is the theoretical radiation that would be emitted by a perfect absorber and emitter of all incident radiation. Its spectral energy distribution is a function solely of the object's absolute temperature, as described by Planck's law.
Usage Examples
- Noun:
- The study of blackbody radiation was fundamental to the development of quantum mechanics.
- Astronomers analyze the blackbody radiation from stars to determine their temperatures.
- The cosmic microwave background is a near-perfect example of blackbody radiation.
Advanced Usage
"Planckian radiation": A technical synonym emphasizing its description by Max Planck's law.
- The curve of Planckian radiation fits the observed data perfectly.
"Cavity radiation": Refers to the same phenomenon, as an idealized blackbody can be modeled by radiation within a cavity in thermal equilibrium.
- In the laboratory, cavity radiation is used to approximate a blackbody source.
Variants and Related Words
Blackbody (n): The idealized physical body that absorbs all incident electromagnetic radiation and is a perfect emitter.
- A small hole in the wall of a large cavity behaves almost like a blackbody.
Thermal radiation (n): Electromagnetic radiation generated by the thermal motion of particles in matter. Blackbody radiation is a specific, ideal case of thermal radiation.
- The heat you feel from a fireplace is due to thermal radiation.
Synonyms
- Cavity radiation: (Physics) Radiation in thermal equilibrium within a cavity.
- Planckian radiation: (Physics) Radiation whose spectrum follows Planck's law.
- Full radiation: (Archaic/Terminology) An older term for the complete spectrum emitted.
Related Concepts (Not Phrasal Verbs)
- Stefan-Boltzmann law: States that the total energy radiated per unit surface area of a blackbody is proportional to the fourth power of its absolute temperature.
- Wien's displacement law: Describes how the peak wavelength of blackbody radiation shifts with temperature.
- Ultraviolet catastrophe: The historical failure of classical physics to predict the correct blackbody spectrum, which was resolved by Planck's quantum theory.
Noun
- the electromagnetic radiation that would be radiated from an ideal black body; the distribution of energy in the radiated spectrum of a black body depends only on temperature and is determined by Planck's radiation law