Light intensity
# Light intensity

Several measures of light are commonly known as intensity:

* Radiant intensity, a radiometric quantity measured in watts per steradian (W/sr)
* Luminous intensity, a photometric quantity measured in lumens per steradian (lm/sr), or candela (cd)
* Irradiance, a radiometric quantity, measured in watts per square meter $(W/m^2)$
   * Intensity (physics), the name for irradiance used in other branches of physics $(W/m^2)$
* Radiance, commonly called "intensity" in astronomy and astrophysics $(W·sr^{−1}·m^{−2})$
