absorptance The ratio of the luminous or radiant flux absorbed by a body to the flux falling on it. Absorptance is generally represented by the Greek letter α (alpha). By definition, in the case of a blackbody α = 1. Absorptance was formerly known as absorptivity. Related category OPTICS AND OPTICAL PHENOMENA Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |