valaistusintensiteetti

Valaistusintensiteetti, often translated as luminous intensity, is a fundamental photometric measure that quantifies the amount of light emitted by a point source in a particular direction. It is defined as the luminous flux per unit solid angle. The SI unit for luminous intensity is the candela (cd). One candela is equivalent to one lumen per steradian (lm/sr).

Luminous intensity is particularly useful when describing the output of directional light sources, such as spotlights or LEDs, where the light is concentrated in a specific beam. It is distinct from luminous flux, which measures the total amount of visible light emitted by a source in all directions. Luminous intensity takes into account the perceived brightness of light by the human eye, as the candela is based on the luminous efficacy of light at a standard wavelength of 555 nanometers, which corresponds to the peak sensitivity of the human visual system.

In practical applications, luminous intensity helps in designing lighting systems, determining the required brightness of bulbs for specific tasks, and comparing the performance of different light sources. For instance, a high luminous intensity reading in a particular direction indicates that a light source is very bright when viewed from that angle. Understanding luminous intensity is crucial for ensuring adequate illumination levels and creating comfortable visual environments.