Question

Well, today our teacher was taking up the topic Radiation under the chapter Properties of Matter. And he said that all bodies with a temperature above zero kelvin emit EM waves with all wavelengths right from zero to infinity units. I just want to know how can we just say it like that, I mean ther must be some proof to this statement. I asked him then and there, but he just said that it was not in JEE syllabus. Please tag me if you are aware of any proof as such (mathematical, of course).

Answer 1

All bodies above zero kelvin emit EM waves across all wavelengths due to blackbody radiation principles; this idea is supported by Wien's displacement law, the Stefan-Boltzmann law, and Planck's quantization of energy, which collectively explain the observed radiation spectrum.

Step-by-step explanation:

The statement that all bodies with temperatures above zero kelvin emit electromagnetic (EM) waves of all wavelengths has its basis in the study of blackbody radiation. A blackbody is an idealized object which perfectly absorbs and emits radiation across the entire electromagnetic spectrum.

As objects get hotter, they emit more radiation and the peak of the emitted spectrum shifts to shorter wavelengths, according to the Wien's displacement law. Furthermore, the Stefan-Boltzmann law states that the total energy radiated across all wavelengths is proportional to the fourth power of the object's absolute temperature (T4). The quantization of energy and the explanation for the distribution of emitted wavelengths were discovered by Max Planck, who introduced the concept that energy is exchanged in discrete quanta. This resolved the so-called 'ultraviolet catastrophe' and led to the development of quantum mechanics.