Wikipedia:Reference desk/Archives/Science/2024 September 27

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September 27

Demonstration of Planck's law in radiation power per unit area?

To demonstrate his law, Max Planck converted radiation power measurements per unit area into energy density ($\times 4\pi /c$).
Is there a demonstration directly with the radiation power from the experiment without conversion into energy density?
I can't find any, but maybe I'm not seeing the correct wording for search engines.
Malypaet (talk) 21:28, 27 September 2024 (UTC)

The Stefan-Boltzmann constant can be derived by integrating the spectral radiance of a blackbody. Spectral radiance is the power emitted by a surface per unit area per unit solid angle per unit frequency (or wavelength). The Stefan-Boltzmann law states that the power radiated per unit area of a black body is proportional to the fourth power of its absolute temperature. Answer generated with Bing CoPilot — Preceding unsigned comment added by 217.180.227.58 (talk) 20:38, 30 September 2024 (UTC)

Unsuitable tool! Malypaet (talk) 20:22, 2 October 2024 (UTC)

Unsuitable how? The Stefan–Boltzmann law derived from Planck's law by considering a small flat black body surface radiating out into a half-sphere has been used to find the temperature of the Sun, other stars and an Effective temperature of the Earth. Philvoids (talk) 14:56, 3 October 2024 (UTC)

My question was about the demonstration of Planck's law, which does not use the same SI units as the Stefan-Boltzmann law. So, is there a demonstration that stays in spectral radiance from the beginning to the end without converting into spectral energy density and back to give the result in spectral radiance? Malypaet (talk) 20:07, 3 October 2024 (UTC)