ABSTRACT
The prism spread the sun’s rays into a spectrum from violet to red. Herschel placed a thermometer in the violet color and recorded the temperature. The names given to various parts of the electromagnetic spectrum are arbitrary but are standardized throughout the physics and electrical communities. The designations of very high frequency and ultrahigh frequency are the only subdivisions used for these longer waves. Scientists after Herschel spent the next 100 years attempting to establish the relationship between temperature and wavelength. They soon recognized that the infrared portion of the spectrum is based on a point where the human eye no longer responds. Radiometry concerns that measurement of the power or flux of electromagnetic radiation between a target source and its associated backgrounds through the intervening media to the detector or receiver. The hatched lines represent emitted radiation, while the open lines represent reflected or scattered radiation.
