How is an object classified based on its ability to reflect electromagnetic radiation?

The classification of an object based on its ability to reflect electromagnetic radiation is most accurately described by the term "reflectivity." Reflectivity refers to the proportion of incident electromagnetic radiation that is reflected by the surface of an object. It is closely linked to how surfaces interact with light, which determines their appearance and how they are perceived in various applications, such as remote sensing and optical analysis.

While emittance, absorbance, and radiance are related concepts in the study of electromagnetic radiation, they represent different characteristics. Emittance refers to the ability of a surface to emit thermal radiation, absorbance quantifies the fraction of incident radiation that is absorbed by a material, and radiance measures the amount of radiation that passes through a unit area in a specific direction.

Thus, when assessing an object's classification based on how it reflects electromagnetic radiation, reflectivity is the most relevant descriptor.