Understanding Thermal Radiation

thanks to curiosity stream for sponsoring this video did you know that any object that has a temperature greater than absolute zero is constantly emitting electromagnetic waves that travel through space at the speed of light it's these electromagnetic waves that produce thermal radiation along with conduction and convection thermal radiation is one of the three ways in which heat transfer

can occur between different objects whether it's to design photovoltaic cells heat exchangers or energy efficient structures Engineers need to be able to model the effects of thermal radiation and a good way to start is by taking a closer look at the electromagnetic waves themselves a first observation we can make is that these waves travel in a

straight line from the emitter they can also travel through a vacuum which gives thermal radiation one of its unique properties unlike conduction and convection it can occur in the absence of a medium an electromagnetic wave is characterized by its wavelength

Lambda radio waves for instance are just electromagnetic waves with very long wavelengths and gamma rays and x-rays are electromagnetic waves with short wavelengths visible light has a wavelength between around4 and7 microns the thermal radiation emitted by an object due to its temperature has a wavelength between .1 and 100 microns it overlaps with the UV visible and

infrared parts of the [Music] spectrum the total energy radiated by a body each second per unit area is called the emissive power e it has units of watts per square meter to study thermal radiation it's useful to define a perfect emitter that emits the maximum possible amount of thermal radiation at a given