This document compares the luminous efficacy, or amount of visible light emitted per watt of power, of various lighting sources. Luminous flux is the highest at 225 lumens per watt for theoretical maximum white light, followed by low pressure sodium lamps at 100-140 lumens per watt and high pressure sodium lamps at 80-125 lumens per watt, with other sources like metal halide, mercury vapor, and fluorescent lamps emitting 50-100 lumens per watt, incandescents only 6-9 lumens per watt, and infrared lamps just 1.4 lumens per watt.

1. Luminous Flux

2. Luminous Efficacy 225 L/W Theoretical max for white light 180 L/W Low Pressure Sodium Lamps 100-140 L/W High Pressure Sodium Lamps 80-125 L/W Metal Halide Lamps 50-60 L/W Mercury Vapor Lamps 35-100 L/W Fluorescent Lamps 10-40 L/W Incandescent Lamps 6-9 L/W Infrared Lamps 1.4 L/W Edison's first lamp EFFICACY LIGHT SOURCE

3. Luminous intensity

4. Illuminance E = F A = Lumens Area = Lux (Lumens per m 2 )