Simply expressing, the black-body radiation problem having a finite energy spectrum, which was behind this Planck's quantum theory.

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Dinesh

Simply expressing, the black-body radiation problem having a finite energy spectrum, which was behind this Planck's quantum theory.

I know what is written in text books of quantum theory. I want to know how they have concluded it.

Dear Chandra,

The absorption and emission of the electromagnetic waves by what is called a "blackbody" has a discontinuity that nobody could explain. Experimentally it was measured with great accuracy that a great values of the wavelengths the electromagnetic radiation absorption follows quite well the Rayleigh–Jeans Law but it failed at low wavelengths, On the other hand at low wavelenghts followed Wien's Law which failed at high wavelengths. How to solve it? Planck assumed the quantization of the electromagnetic radiation in such a form that the distribution of radiation where a Bose-Einstein formula which contains Rayleigh-Jeans and Wien's Laws as particular cases. Thus this allowed to find one only law of radiation of the black body and to understand that the electromagnetic field were in fact a collection of particles (bosons) called by Einstein photons. This is a broad explanation of how the h Plack constant has arisen in Physics.

The question can be put more broadly: how a new physical theory of the quantum theory type is born. Now, for example, a quantum-classical theory is being born:

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“…What is history behind discovery of planck's constant ?..”

the history behind the discovery of the Planck’s constant in 1900, when Planck discovered the fact of quantum nature of radiation of light, was followed by much more fundamental discovery of the Planck units, where the constant “h” is only one from the set of others, first of all Planck length, lP and Planck time, tP.

As that is shown in the Shevchenko and Tokarevsky’s informational physical model https://www.researchgate.net/publication/273777630_The_Informational_Conception_and_Basic_Physics DOI 10.5281/zenodo.16494 , these units with a very large probability are utmost fundamental constants that are basic in the informational system “Matter” and are fundamental parameters of the, first of all binary, 4D fundamental logical elements (FLE) that are primary elements from which every material informational object is built and exchanges by information with other objects. The length and the time are the [at least 4 equal] “sizes” of the elements and “flipping time interval” for FLE to change its state; the Planck constant is fundamental elementary [physical] action, that is necessary to change a state of a material object/system on one bit. Besides it is the fundamental elementary angular momentum, so, when a fermion changes its spin state, again the information changes on one bit; the question “why different on first glance physical parameters “action” and “angular momentum” have the same dimensionality and, why their elementary changes correspond to the same informational change?” is one of utmost fundamental physical problem.

Another example with a large probability every particle is some close-loop algorithm that constantly runs because of the energy conservation law on the FLE “hardware”, and so every particle moves as some constantly “FLE flipping point” as some 4D helix in the Matter’s absolute 4D sub-spacetime [of Matter’s absolute [5]4D Euclidian spacetime]. The radius of this helix seems equal to particle’s Compton length, flipping point moves in the helix section, i.e. the circle, with the speed of light.

So the point’s angular momentum is equal to the reduced Planck constant, ћ, and that is so for photons. However having rest mass fundamental particles, i.e. fermions, have non-integer spin ½ ћ, what follows from that the momentum is defined in this case relating to motions around the coordinate time, τ- axis [in the 4D sub-spacetime above], what is fundamental; and around some spatial axis, since the space is 3D.

However if a rest mass particle moves in the 3D space, say, along the X-axis, then it rotates in the (X,cτ) plain so that it’s “fundamental” spin projection on the X-axis becomes be non-zero, and for fast approaches to its value, i.e. to ћ. This effect in physics is known as “particle’s helicity”, and was measured for neutrinos and electrons.

From that follows, besides that neutrinos have rest masses, that if a particle is a boson and has, at that, a rest mass, then rather probably this particle isn’t fundamental and consists of some other particles. Including the exotic " very many Bevs” bosons that were discovered in last two decades are so either compound particles or possiblyhaving spins be equal 2. That could be checked if it would be possible to measure their helicities, but that seems not now.

More about the informational model and so, of course, about the Planck constant and other ultimately fundamental Planck constants see the paper that is linked above and, for example, SS posts in the thread https://www.researchgate.net/post/What_are_the_interpretations_of_Planck_length?view=5b1bf0ebeb87033da0495795

Cheers