The word bold was named by Kirchhoff in 1862, and thermodynamics was introduced. Light radiated by blackbody is called blackbody radiation.
The radiation power p per unit surface area of a blackbody is directly proportional to the fourth power of its temperature, that is, P=σ, where σ is called steffen-Boltzmann constant, also known as steffen constant.
Because blackbody can be used to test the nature of heat balance, and its radiation follows thermodynamic scattering, the study of blackbody in history has become an opportunity for quantum physics to begin.
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Application of black body:
Blackbody is mainly used in the field of temperature measurement in industry, and the main product is blackbody furnace.
In the calibration and verification of radiation thermometers, the comparison method is usually adopted, that is, through the radiation source with high stability (usually blackbody radiation source) and other supporting equipment, the standard reappearance temperature is compared with the reappearance temperature of the measured radiation thermometer, so as to judge whether it is qualified or give the calibration result.
In the calibration and verification work, in general, the radiation source can be an open medium-low temperature blackbody furnace within the range of -6 ~ 1 200℃ (or 1 600℃), or a high-temperature blackbody furnace with vacuum pumping and inert gas protection at 1 200℃ ~ 3 200℃.
The standard devices are second-class standard thermocouple (second-class standard platinum resistance thermometer) and standard optical (photoelectric) pyrometer respectively.
Reference source: Baidu Encyclopedia-bold.