Sentences with phrase «unit emittance»

Not exact matches

«The Stefan — Boltzmann law states that the total energy radiated per unit surface area of a black body across all wavelengths per unit time (also known as the black - body radiant emittance or radiant exitance) is directly proportional to the fourth power of the black body's thermodynamic temperature».

Well from a computational accuracy point of view, the measure of intensity is accurate to better than 1 % so long as you are more than 10 emitting surface diameters away from a non-point source; but the point is there is NO per unit area section in an Intensity specification; but there is in Radiance, or Spectral Radiance, which these graphs properly are, and also in «emittance» which is simply W / m ^ 2 without regard for directional properties, or wavelength or frequency properties, which would intorduce the spectral terms at least.