What is needed for heat transfer by radiation?
Answers
Explanation:
Heat transfer is mainly divided to 3 sub-categories- Conduction, Convection and Radiation.
Among others, heat transfer via radiation is based on the physical phenomenon called "Black-body radiation".
According to the scientific model of this phenomenon, every matter in a temperature greater than the absolute zero (0 degrees K) emits electromagnetic radiation, because of oscillations of charged particles inside it (temperature is related to the average kinetic energy of particles- when there is kinetic energy- there will be oscillating charged particles).
So every matter in our universe emits radiation. "How much" radiation, and how strong this radiation is? In other words- what is the intensity of the emitted radiation, and in what frequency it is emitted?
There are several laws in thermodynamic physics related to the intensity an wavelength (frequency) of thermal radiation, such as:
Planck's law determines the "spectral radiance" of black-body- i.e. the amount of energy this body emits in each wavelength along the electromagnetic spectrum, for a specific temperature.
Stefan-Bolzman's law determines the total amount of energy emitted via radiation for a body in a specific temperature (in all the wavelengths).
Wein's displacement law determines the frequency in which a body will emit the most powerful electromagnetic radiation.