Light intensity
From Wikipedia, the free encyclopedia
Several measures of light are commonly known as intensity. These are obtained by dividing either a power or a luminous flux by a solid angle, a planar area, or a combination of the two. The relationships are summarised in the table below:
| Radiometric | Photometric | |
|---|---|---|
| Angular | Radiant intensity, measured in watts per steradian (W/sr) | Luminous intensity, measured in lumens per steradian (lm/sr), or candela (cd) |
| Areal |
Irradiance, measured in watts per square meter (W/m2), called intensity in most branches of physics |
Several quantities measured in lumens per square meter (lm/m2), or lux (lx):
|
| Both | Radiance, commonly called intensity in astronomy and astrophysics (W·sr−1·m−2) | Luminance (lm·sr−1·m−2, or cd/m2) |
[edit] See also
- Brightness, the subjective perception elicited by the luminance of a source
- Photometry (optics)
- Photometry (astronomy)
- Radiometry
