Phot

For the 9th-century theologian and scholar, seePatriarch Photius I of Constantinople.

Aphot(ph) is aphotometricunit ofilluminance,orluminous fluxthrough an area. It is not anSIunit but rather is associated with the oldercentimetre–gram–second system of units.The name was coined byAndré Blondelin 1921.

Phot
Unit system	CGSunits
Unit of	Illuminance
Symbol	ph
Conversions
1 phin...	... is equal to...
SI derived unit	10000lx
SAEunits	929fc

Metric equivalence:

$1\ \mathrm {phot} =1\ {\frac {\mathrm {lumen} }{\mathrm {centimetre} ^{2}}}=10,000\ {\frac {\mathrm {lumens} }{\mathrm {metre} ^{2}}}=10,000\ \mathrm {lux} =10\ \mathrm {kilolux}$

Metric dimensions:

Illuminance =luminous intensity×solid angle/ length²

See also

• Illuminance
• Lumen (unit)
• Lux
• Photometry (optics)
• Light

External links

• Knowledgedoor, LLC (2005).Library of Units and Constants: Illuminance Quantity.Retrieved 2006-07-21.
• Illuminance Converter.Retrieved 2006-07-21.