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I have some questions related to radio waves, photons and propagation , transmission and reception.

It’s my understanding a radio wave is a changing electrical and magnetic field that travels through space. It’s also my understanding it consists of photons. Is there any relationship between these fields and the photons of the wave? For instance, is the position or quantity of photons determined by the EM field?

My understanding is that a polarized electrical field will cause electrons in the wavefront to move, possibly colliding with other electrons and releasing photons, but am unsure.

C. Huygens believed that EM radiation propagates as spherical wavefronts, which I assume consist of EM radiation and photons. These wave fronts interfere to creates new wave fronts. I’m assuming the shell of the sphere represents a positive electrical field and the enclosed volume represents the negative field. Is this description correct, if not what is?

Finally, when a radio transmits it’s my understanding it oscillates voltage on an antenna conductor. This creates redox chemical reactions where electrons move from the conductor to ground side of the dipole and vice versa. The outcome of this is EM radiation as a wavefront. It’s my understanding the wavefront photons are created by electrons colliding with each other, releasing photons. Do these electrons travel with the released photons or does this wave create its own self propagating EM field?

For wave reception my understanding the EM wave crosses the antenna and the electrical field causes electrons in the antenna wire to move, but unsure how this polarized one conductor positive and the other negative. Does anyone know?

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For instance, is the position or quantity of photons determined by the EM field?

Yes. Each photon represents a certain amount of energy. Therefore the density of photons (in number per unit volume) is proportional to the square of the field strength at any point.

My understanding is that a polarized electrical field will cause electrons in the wavefront to move, possibly colliding with other electrons and releasing photons, but am unsure.

There are no electrons associated with the propagating EM wave in space. The wave propagates as a disturbance in the electromagnetic field, not a motion of charged particles.

As an analogy, if I throw a rock into a pond to create a wave on the surface of the pond, the rock doesn't have to move for the water to continue rippling.

I’m assuming the shell of the sphere represents a positive electrical field and the enclosed volume represents the negative field. Is this description correct, if not what is?

The field oscillates back and forth between "positive" and "negative" (which you may arbitrarily define by defining your coordinate system either rightside-up or upside-down), at any point in space.

The "shell" in the Huygens concept, is purely a mathematical concept. We could consider such a shell (or surface) anywhere in space. There is no physical distinction or difference in the behavior of the field between the region inside the shell and outside the shell.

This creates redox chemical reactions where electrons move from the conductor to ground side of the dipole and vice versa.

Metals contain a high density of mobile electrons. There's no need for a chemical reaction to make mobile carriers available in a metal.

It’s my understanding the wavefront photons are created by electrons colliding with each other, releasing photons.

Any time a charged particle accelerates, it disturbs the electric field, and this will initiate an EM wave. In an antenna, the overall motion of large numbers of electrons moving together is much more important than the motion of one individual electron colliding with another one.

Do these electrons travel with the released photons or does this wave create its own self propagating EM field?

Unless the beam is at high enough frequency to produce the photoelectric effect, the electrons remain confined within the material of the antenna.

For wave reception my understanding the EM wave crosses the antenna and the electrical field causes electrons in the antenna wire to move, but unsure how this polarized one conductor positive and the other negative. Does anyone know?

If more electrons move towards one end of the antenna, that end becomes negatively charged. Since there are excess nuclear charges (protons) left at the other end of the antenna, that end becomes positively charged.

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  • $\begingroup$ Really nice answer. $\endgroup$ May 25, 2022 at 3:17
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There are many questions here, I'll address some of them.

Your concept of radio waves is basically correct. For relatively long radio wavelengths (like AM radio for example) the photons have such low energy that they cannot easily be detected as individual photons and it is instead customary to model their behavior as ripples of the electromagnetic field that spread spherically into space.

Electrical charges do not distribute themselves in an EM wave as you have described it. The strength of the electric and magnetic field components in a passing EM wave rise and fall but there is no net space charge redistribution left behind the traveling wave.

There are no redox chemistry reactions occurring in a dipole radio antenna. What happens is that the current being driven into the antenna wire by the transmitter connected to it sets up a "sloshing" motion of electrical charges in it that flow back and forth from one end of the wire to the other over and over again, thereby radiating electromagnetic waves into the space surrounding the wire.

Those EM waves are not caused by electrons colliding and bouncing off each other inside the wire, and ordinarily those electrons do not ever physically leave the wire- unless you touch it. For a transmitter pumping 100 watts or so into the antenna wire, the resulting electric shock will be enough to kill you, or at least give you severe burns on your skin.

An EM wave intersecting a wire in free space will induce a current to flow first in one direction, then backwards, then forwards, etc. causing the current in the antenna to alternate between positive and negative directions.

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