ISO/TC 211 Multi-Lingual Glossary of Terms (MLGT)

perfect blackbody

perfect absorber (and therefore the best possible emitter) of thermal electromagnetic radiation, whose spectral radiance density (or spectral brightness density, ${\displaystyle L_{\text{f}}}$ ) is given by the Planck formula ${\displaystyle L_{\text{f}}=\frac{2\text{h}{\nu }^3}{{\text{c}}^2(e^{\text{h}\nu /\text{k}T}-1)}}$ where ${\displaystyle v}$ is the frequency in Hz; ${\displaystyle \text{h}}$ is Planck’s constant (${\displaystyle 6.62607\times {10}^{-34}\text{J}\cdot \text{s}}$ ); ${\displaystyle \text{k}}$ is Boltzmann’s constant (${\displaystyle 1.38064852\times {10}^{-23}\text{J}/\text{K}}$ ); ${\displaystyle T}$ is physical temperature of the blackbody in K; ${\displaystyle \text{c}}$ is velocity of light (${\displaystyle 2.997925\times {10}^8\text{m}/\text{s}}$ ). ${\displaystyle \text{e}}$ is the base of natural logarithm

[SOURCE: ISO/TS 19159-4:2022, 3.30]