The luminous efficacy is a measure that indicates how efficient a light source is. Compact fluorescent lamp/energy-saving lamp: with 15 W electrical power: luminous flux Φ = 900 lm Incandescent lamp with 15 W electrical power: luminous flux Φ = 90 lm

Two examples of typical luminous flux values: Short wavelengths are termed ultraviolet and longer waves are termed infrared. How bright and colourful the human eye can perceive a light depends on the wavelength of the radiation and the intensity with which the radiation hits the retina. When visible light is emitted, this is also called luminescence. Light is created when energy is converted. They travel in waves and transmit energy impulses. Light consists of photons, also called light particles. The total luminous flux emitted by a light source over a certain period of time. The ratio of emitted luminous flux to required electrical power. The measure for the impression of brightness of a surface, perceived by the human eye. The measure for the light that arrives at a receiver surface. Gives information about how much light is radiated in a certain direction. The measure for the total amount of light emitted by a light source. The following table provides an overview of the most important photometric quantities and units: Photometrische Größe In light measurement, a distinction is made between various photometric quantities by which the unit of light intensity can be evaluated. Important photometric quantities and units

Light beam intensity equation