Radiation: Emission and Absorption

This lecture covers the fundamentals of radiation heat transfer, including emission and absorption processes, Kirchoff's law, and the absorption factor. It also explores examples of radiation exchange between different surfaces, such as black and gray opaque surfaces, and surfaces separated by a semi-transparent medium. The concept of radiosity, which combines emitted and reflected flux, is discussed in detail. Various scenarios, such as radiation between multiple surfaces forming a closed enclosure and the behavior of thermocouples in different configurations, are analyzed. The lecture concludes with the study of radiation exchange in complex systems, like between gray opaque surfaces separated by a semi-transparent medium.