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Why we can see photons which are a combination of electric and magnetic fields, but we can't see electric and magnetic fields produced by a current say? If we are not seeing the electric and magnetic fields in the photon when we see it, then what we are seeing instead? As far as I know a photon is simply an electromagnetic wave. If it's about frequency, then can we see an electric field with a frequency inside our vision spectrum?

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    Keep in mind most electric fields and magnetic fields that we call electric and magnetic fields are waaaaayyyyy below the frequency of visible light. On the other hand, radio noise is emitted all the time by things like motors and circuits. – DKNguyen Jul 12 '21 at 21:03
  • It’s the other way around. The Electromagnetic field is made of billions of individual photons. – Bill Alsept Jul 13 '21 at 00:56

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If we are not seeing the electric and magnetic fields in the photon when we see it, then what we are seeing instead?As far as I know a photon is simply an electromagnetic wave

The photon has no electric and magnetic field. It is an elementary point particle of mass zero, spin +/-1 and energy = h ν where ν is the frequency that a large number of photons build up quantum mechanically into the classical electromagnetic wave.

Seeing is a biological process and it depends on cells in the retina of the eye, whose atom absorb optical frequency photons creating signals towards the brain.

How atoms are excited by photons and release photons is by energy level transitions of atoms . See here for the simple hydrogen atom.

Electric and magnetic fields cannot directly affect atomic energy levels. See my answer here.

anna v
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  • Then again, there's the recent slightly wacky model which states there are no particles, and no matter at all, just highly localized fields (or highly localized probability states, if you like). I'm not advocating this but think it's fun. – Carl Witthoft Jul 13 '21 at 13:18
  • 'Electric and magnetic fields cannot directly affect atomic energy levels' They certainly can. There are the Stark and Zeeman effects, magnetic dichroism, electron paramagnetic resonance and related techniques. Transition energy and probability are affected. – my2cts Jul 13 '21 at 14:54
  • @my2cts did you notice the "directly". I did not want to go into the subject of virtual photons. – anna v Jul 13 '21 at 15:27
  • @AnnaV To explain for example the Stark effect no virtual photons are needed. – my2cts Jul 13 '21 at 22:25
  • @my2cts the question is about "photons", i.e quantummechanics. in QM there are always virtual photons for higher order effects https://en.wikipedia.org/wiki/Stark_effect#Perturbation_theory – anna v Jul 14 '21 at 03:57