Fundamentals of thermal radiation

This chapter provides a background on thermal radiation, which is considered as the third mechanism of heat transfer after conduction and convection. It explains that the transfer of heat is a mechanism of energy transfer and is aimed at achieving thermal equilibrium and equal temperatures. It also points out that thermal radiation is an emission of electromagnetic waves which can be transferred between two bodies even if they are separated by a vacuum. The chapter considers thermal radiation as an electromagnetic radiation that is attributed to velocity, frequency, and wavelength. It discusses the radiation emitted and not equally distributed over a wide range of wavelengths, which is referred to as spectral distribution or spectrum.