Conclusion - Lyrics - Radiance

Radiance and spectral radiance are measures of the quantity of radiation that passes through or is emitted from a surface and falls within a given solid angle in a specified direction. They are used in radiometry to characterize diffuse emission and reflection of electromagnetic radiation. In astrophysics, radiance is also used to quantify emission of neutrinos and other particles. The SI unit of radiance is watts per steradian per square metre , while that of spectral radiance is W·sr−1·m−2·Hz−1 or W·sr−1·m−3 depending on whether the spectrum is a function of frequency or of wavelength. ...