Radiometric and Photometric Quantities

Radiometric 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) E_e – Irradiance E_v – Illuminance M – Exitance (Luminous or radiant) I – Intensity (Luminous or radiant) L_e – Radiance L_V – Luminance r – Distance ω – Solid Angle

Conversion Equation from Radiometric Quantity to Photometric Quantity

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