intensitats

Intensitats is the plural of intensitat, a term used in Catalan to describe the magnitude of a physical quantity that measures the strength, concentration, or rate of energy flow in space. The concept is used across disciplines such as optics, acoustics, and spectroscopy to express how much of something passes through a given surface or travels in a given direction, often per unit area or per unit solid angle.

In photometry and radiometry, radiant intensity I is the power per unit solid angle emitted by a light source, with SI unit watt per steradian (W·sr−1). The photometric counterpart, luminous intensity Iv, is the luminous flux per unit solid angle and is measured in candelas (cd). Luminous intensity takes into account the eye’s sensitivity to different wavelengths, so sources with equal radiant intensity can have different Iv.

Irradiance E describes the radiant power per unit area incident on a surface (W/m^2). The relation between intensity and irradiance depends on geometry: E is the integral of I over the relevant solid angle with a cosine factor.

In acoustics, sound intensity is the mean energy flow per unit area (W/m^2) and relates to pressure and particle velocity in the wave.

In spectroscopy, intensitats d’emissió o absorció indicate the strength of a spectral feature, often proportional to concentration and path length.

Measurement relies on instruments such as photometers, radiometers, spectrometers, and sound level meters. Understanding intensitats supports applications in lighting design, imaging, environmental monitoring, and signal processing.