Illuminance

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2-1-055

Illuminance (at a point of a surface)

The quotient of the luminous flux (dF) incident on an infinitesimal element of the surface containing the point under consideration, by the area (dA) of that element.

Ch2 Fig3.jpg

Symbol: E

Unit: lux (lx)

lumen per square metre (lm/m2)

Reference: C.I.E. (modified)


Note 1: If the luminous flux may be considered uniformly distributed over a finite plane surface of area A, the illuminance on this surface is given by

(Equation)

where F is the total luminous flux incident on the surface.


Note 2: The continued use of the former term Illumination with the meaning above is now deprecated as this use conflicts with the general meaning of the term (2-5-010).




Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)

Illuminance

Energy

square metre

Contrast

Celsius (previously Centigrade)

Capacitance

charge current

Intensity

nertia of the water plane

ampere

force

Farad

Fahrenheit

International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM