Stefan's law

/ ˈstɛfənz /

noun

1. 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 ^–8Wm ^–2K ^–4 Also calledStefan-Boltzmann law

Word History and Origins

Origin of Stefan's law¹

C19: named after Josef Stefan (1835–93), Austrian physicist

Example Sentences

So far as the experimental results available at that time were concerned, Stefan’s law could be regarded only as an empirical expression of doubtful significance.

From Project Gutenberg

This result is usually known as Stefan's Law.

From Project Gutenberg

According to Stefan’s Law, the radiation varies for a perfect radiator with the 4th power of the absolute temperature; so that if Mars were at 124° abs., while the Earth were at 289° abs., the Earth would be radiating its heat nearly 30 times faster than Mars.

From Project Gutenberg

Coming now to the special feature of Mars and its probable temperature, we find that most writers have arrived at a very different conclusion from that of Mr. Lowell, who himself quotes Mr. Moulton as an authority who 'recently, by the application of Stefan's law,' has found the mean temperature of this planet to be-35° F. Again, Professor J.H.

From Project Gutenberg

This however is the amount of radiation measured by the Bolometer, and to get the temperature of the radiating surface we must apply Stefan's law of the 4th power.

From Project Gutenberg