Monday, 8 April 2019

What is Planck's quantum theory of radiation?


In Planck's quantum theory of radiation we get to know light travels not continuously but discontinuously in the form of small packets of energy called quantum..... Does it means in short means that light dosnt travels in form of a wave but as a particle as if it would have traveled as a wave it would be continuous?



Answer



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The classical mode leads to the ultraviolet catatstrophy, because all possible frequencies have equal probability of being occupied by radiation.



The quantized modes repress the higher frequencies, which is what is observed experimentaly.


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The formula used


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leads to the conclusion that each frequency comes in packets with energy = h*nu


There is a continuum of frequencies, but less occupied as the frequencies go up, in the cavity model used.


It is the photoelectric effect that identified the photon particle with energy=h*nu , and the spectra of the atoms.


Present quantum field theory explains classical electromagnetic radiation as emergent from zillions of photons, as can be seen here.


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