Stefan-Boltzmann constant

From Wikipedia, the free encyclopedia

The Stefan-Boltzmann constant (also Stefan's constant), a physical constant denoted by the Greek letter σ, is the constant of proportionality in the Stefan-Boltzmann law: the total energy radiated per unit surface area of a black body in unit time is proportional to the fourth power of the thermodynamic temperature.

The value of σ is 5.670 400(40)×10−8 W·m-2·K-4. This value is derivable as well as experimentally determinable; see Stefan-Boltzmann law.

σ can be defined in terms of the Boltzmann constant kB as:

\sigma = \frac{2\pi^5k_{\mathrm B}^4}{15h^3c^2} = \frac{\pi^2k_{\mathrm B}^4}{60\hbar^3c^2},

where h is Planck's constant, \hbar = h/2\piis Dirac's form of Planck's constant, and c is the speed of light in a vacuum.

A related constant is the radiation constant ([1]) which is equal to

\frac{4\sigma}{c}.

Advanced Search
Included Web Search Engines


Safe Search

close

Top Matching Results

Occasionally Search.com will highlight specialized results that are based on the context of your query. Examples of specialized results include specific links to news, images, or video.

Top Matching Results may highlight information from other Search.com pages, content from the CNET Network of sites, or third party content. The listings are based purely on relevance. Search.com does not receive payment for listings in this section but our partners that provide this data may get paid for listing these products.

Sponsored Links

This section contains paid listings which have been purchased by companies that want to have their sites appear for specific search terms and related content. These listings are administered, sorted and maintained by a third party and are not endorsed by Search.com.

Search Results

Search.com sends your search query to several search engines at one time and integrates the results into one list which has been sorted by relevance using Search.com's proprietary algorithm. You can customize the list of search engines included in your metasearch from the preferences.

The search engines that are used in your metasearch may allow companies to pay to have their Web sites included within the results. To view the Paid Inclusion policy for a specific search engine, please visit their Web site. Search.com does not accept payment or share revenue with any search engine partner for listings in this section.