| 释义 |
Stefan's law
Stefan's law (ˈstɛfənz) n (General Physics) the principle that the energy radiated per second by unit area of a black body at thermodynamic temperature T is directly proportional to T4. The constant of proportionality is the Stefan constant, equal to 5.670400 × 10–8 Wm–2 K–4. Also called: Stefan-Boltzmann law [C19: named after Josef Stefan (1835–93), Austrian physicist]Stefan's law
Stefan's law (steff -ănz) (Stefan-Boltzmann law) The law relating the total energy, E , emitted over all wavelengths, per second, per unit area of a black body, with the temperature, T , of the body: E = σT 4 σ is Stefan's constant, which has the value 5.6705 × 10–8 W m–2 K–4. The law can be derived from Planck's radiation law (see black body), but was first deduced by Josef Stefan in 1879 and then derived from thermodynamics by Ludwig Boltzmann in 1884. See also luminosity. |