Stefan's law /ˈstɛfənz/

• 1. 

  N the principle that the energy radiated per second by unit area of a black body at thermodynamic temperature T is directly proportional to T 4. The constant of proportionality is the Stefan constant, equal to 5.670400 × 10–8 Wm–2 K–4 斯特藩定律 (Also called Stefan-Boltzmann law)