Electromagnetic radiation, absorption wave lengths

When radiation hits a body, some of it will be reflected, some absorbed and some transmitted. These portions are represented by the reflectivity r, the absorptivity a, and the transmissivity r. These three dimensionless quantities are not purely properties of the irradiated material, they also depend on the kind of radiation which strikes the body. Of main influence is the distribution of radiation over the wave length spectrum of the electromagnetic waves incident on the material. However it can always be said that... 

---