HOW do radio waves form at the subatomic level?

[taylaron]

Do you feel comfortable at this point with Maxwell's description, or do you need more details on it?

This discussion has clarified my understanding of Maxwells equations. However, it seems obvious to me that my understanding is limited until I can comprehend the mathematics associated with them.

Accelerating and decelerating electrons produce a varying electric field around the antenna. This field in turn produces the magnetic 'other half' of the electromagnetic wave.

Haha, now we're getting into the particle-wave duality phenomenon. Your statement above seems completely logical and easy to understand in terms of fields, but some (all?) EMR's ability to behave like particles provokes more debate on what EMR actually is.
I don't know where I'm going with particle-wave duality, but it bothers me that EMR can be easily explained as a wave (above), but not so easily as a particle.
Any thoughts?

 

[map19]

The photon is the quantum of electromagnetic energy.
It contains energy E = hf. So its energy is proportional to frequency.
It is a mathematical construct to explain how a quantum can be seen as a particle.
The electromagnetic waves are propagated in space at C (or close to it in air ) and can easily be measured and shown on an oscilloscope.
Some experiments rely on the packet nature of the quantum to 'count' photons.
They have no existence outside the electromagnetic wave field.

This is easily seen where isotropic propagation over a long distance calculates to one photon per sq m or even per sq km. Where is it exactly ? But the waves, at very low amplitude are still all over the area.

 

[Dale]

it bothers me that EMR can be easily explained as a wave (above), but not so easily as a particle.
Any thoughts?

Again, being easy to explain or easy to visualize is not a requirement for a scientific theory. The only requirement is that it accurately predict the results of experiments. The particle model (QED) predicts the results of certain specific experiments better than the wave model (Maxwell's eqts), but those specific experiments are not relevant to generating typical radio waves in an antenna.

That said, the best non-technical explanation of QED that I have found is a series of three or four lectures by Feynman at the university of Auckland sponsored by the Vega foundation. But to really understand any theory, Maxwell or QED, requires learning the math.

 

[sophiecentaur]

Haha, now we're getting into the particle-wave duality phenomenon. Your statement above seems completely logical and easy to understand in terms of fields, but some (all?) EMR's ability to behave like particles provokes more debate on what EMR actually is.
I don't know where I'm going with particle-wave duality, but it bothers me that EMR can be easily explained as a wave (above), but not so easily as a particle.
Any thoughts?

I think the problem is with the way the word 'particle' was chosen, in the first place. It goes, of course, way back to Corpuscular Theory and seems to have latched on. It implies the notion of a little bullet and carries all those connotations.

For people concerned with short wavelength phenomena, like light, there seems to be less of a problem because photons appear to be fairly localised and it doesn't seem necessary to delve too closely into their 'size'. With RF wavelengths, it gets more awkward to assign a particular extent for the photon. 'Size' is not really a relevant concept for an entity which is traveling at c so I just don't see why we have to have little (or big) bullets. Let's just keep photons as quanta of energy, let them be associated with a wave and stop trying to picture them in a spatial form.

 

[GT1]

Here's a more interesting question: fluorescent molecules are ~10 nm in size, yet the radiation they emit is 50 times that size. Similarly, radio antennas are a small fraction of the wavelength of emitted light. How can this be? How does the photon 'fit' inside the emitter?

So how can we explain it?

 

[f95toli]

Single photons do not have a "size" as such so there is nothing to "fit". Again, for the full explanation you really need QED; there is no simple, classical explanation for how this works,