Physics: Stefan-Boltzmann constant

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Stefan-Boltzmann constant σ = 5.670×10⁻⁸ W/(m²·K⁴) The Stefan–Boltzmann law, also known as Stefan's law, describes the intensity of the thermal radiation emitted by matter in terms of that matter's temperature.

Commentary

Stefan-Boltzmann constant Symbol: σ = 5.670×10⁻⁸ W/(m²·K⁴) The Stefan–Boltzmann law, also known as Stefan's law, describes the intensity of the thermal radiation emitted by matter in terms of that matter's temperature. Why σ matters This constant appears everywhere in physics equations. It defines a fundamental limit or relationship in nature that holds true everywhere in the universe. M ∘ = σ T 4 . {\displaystyle M^{\circ }=\sigma \,T^{4}.} Understanding σ σ = 5.670×10⁻⁸ W/(m²·K⁴) The Stefan–Boltzmann law, also known as Stefan's law, describes the intensity of the thermal radiation emitted by matter in terms of that matter's temperature. It is named for Josef Stefan, who empirically derived the relationship, and Ludwig Boltzmann who derived the law theoretically. For an ideal absorber/emitter or black body, the Stefan–Boltzmann law states that the total energy radiated per unit surface area per unit time (also known as the radiant exitance) is directly proportional to the fourth power of the black body's temperature, T: M ∘ = σ T 4 . {\displaystyle M^{\circ }=\sigma \,T^{4}.} The constant of proportionality, σ {\displaystyle \sigma } , is called the Stefan–Boltzmann constant. It has the value

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