What is a photon in terms of EM waves?

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A photon is the smallest excitation of the quantized electromagnetic field and cannot be accurately described as a classical electromagnetic (EM) wave. It is incorrect to think of a photon as one wavelength of an EM wave; rather, classical EM fields are better represented by coherent quantum states. Quantum electrodynamics provides a broader framework than classical electrodynamics, allowing for the explanation of classical EM waves in terms of photons, but not vice versa. There is no classical analog of a photon, highlighting the fundamental differences between quantum and classical descriptions of light. Understanding these distinctions is crucial for grasping the nature of photons and EM waves.
k9b4
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Is it one wavelength of EM wave? I have googled for this and I can't find an explanation for what a photon is in terms of EM waves.
 
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This is a complicated issue. The photon is the smallest possible excitation of the quantized electromagnetic field. It really does not make much sense to think of it as a classical EM wave, because it is not. Classical EM fields are better described by coherent quantum states.
 
k9b4 said:
Is it one wavelength of EM wave? I have googled for this and I can't find an explanation for what a photon is in terms of EM waves.
It is most definitely not one wavelength of an EM wave.

Quantum electrodynamics (the theory of photons) is a more general theory than classical electrodynamics (the theory of EM waves). Thus, you can explain what classical EM waves are in terms of photons, but not the other way around.

There simply is no classical EM analog of a photon, but there is a quantum analog of a classical EM wave, the coherent state that Orodruin mentioned.
 
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'

Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'

So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...
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