Radiometric and Photometric Quantities

Radiometric Quantities

radiometric quantities

Photometric Quantities

photometric quantities

Subscripts used in Illumination Engineering Notation

S – Source Quantity
D – Detector Quantity
e – Energetic (Radiometric Quantity)
v – Visual (Photometric)

Quantities used in Illumination Engineering Notation

dA – Infinitesimal area element
Q – Energy (Luminous or radiant)
Φ – Flux (Luminous or radiant)
Ee – Irradiance
Ev – Illuminance
M – Exitance (Luminous or radiant)
I – Intensity (Luminous or radiant)
Le – Radiance
LV – Luminance
r – Distance
ω – Solid Angle

Conversion Equation from Radiometric Quantity to Photometric Quantity





Where, Km is the constant which is called maximum spectral luminous efficacy and its value is 683 lm/W.

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