Thermal radiation is characteristically different from conduction and convection in that it does not require a medium and, in fact it reaches maximum efficiency in a vacuum. Thermal radiation is a type of electromagnetic radiation which is often modeled by the propagation of waves. These waves have the standard wave properties of frequency, ν ν and wavelength, λ λ which are related by the equation λ λ = c ν ν where c is the speed of light in the medium.