Koshel, R. John Photon Engineering, LLC, Tucson, Arizona.
Last reviewed:November 2019
- Related Primary Literature
- Additional Reading
The antiquated term for candela (1 cd = 1 lumen/ steradian), which is the unit of measure for luminous intensity. Candlepower (cp) is derived from comparison to the light produced from a standard candle of one-sixth pound (∼75.6 g), pure spermaceti burning at a rate of 120 grains per hour (∼7.776 g/h or 2.16 mg/s). The candela is a fundamental unit of the International System of Units (abbreviated SI due to the French form of Système International d'Unités), and it has the following definition: The candela [candlepower] is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of 540 × 1012 hertz and that has a radiant intensity in that direction of (1/683) watt per steradian. See also: Luminous intensity; Metric system; Physical measurement; Units of measurement
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 10,000 highly qualified scientists and 45 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information