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Randywithout8as t1_j8iw2gt wrote

A lot going on here. I think of a photon as a packet of light energy (frequently this is referred to as a "quantum" of light energy). This packet consists of some electromagnetic distortion. This distortion has a wavelength and a frequency. These values are interchangeable due to the speed of light. Additionally, through the speed of light relationship, the energy of the photon is defined by its wavelength and frequency. We can then measure a photon using a photodetector. Think of a photodetector like a solar panel with more precise electronics. When a photon hits the photodetector, it transfers its energy into a semiconductor, the photon energy is absorbed and converted to electrical energy. The electrical energy is measured and then we can work backwards from electrical energy to photon energy to wavelength.

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Randywithout8as t1_j8iycbc wrote

As far as model 1 vs model 2. They're both kind of incorrect. A photon is not like a neutron. Photons are massless (not exactly because they have momentum, but that's the way it goes...) a photon is also not the "medium" through which EM radiation travels. A photon is a way to "quantize" (or break down into the smallest possible unit/packet/measurable piece) a beam of light.

Another way to view it: When light is emitted, it is quantized (discrete). It is not continuous. When you turn the dimmer switch on an LED, it doesn't produce a bigger or smaller light beam, it produces a larger or smaller number of photons. Each electron you pass through the LED excites an electron to later decay back to ground state. This decay emits a photon. The more electrons you pass through the LED, the more photons get produced, these photons constructively interfere to produce a higher intensity light.

Try not to think of a photon like a tiny ball of something. It is just a term to describe a unit of a type of energy.

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Laetitian t1_j8izs2w wrote

>Another way to view it: When light is emitted, it is quantized (discrete). It is not continuous. When you turn the dimmer switch on an LED, it doesn't produce a bigger or smaller light beam, it produces a larger or smaller number of photons. Each electron you pass through the LED excites an electron to later decay back to ground state.

Though there is also the other way of altering the energy content of a photon, by impacting its frequency (and by extension wavelength.) It's just not useful for affecting the intensity of visible light.

Since we're explaining the photon's essence, I figured making that explicit might help to avoid further confusion.

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platoprime t1_j8jngne wrote

Everything is energy so that's a pretty useless description. Plus photons are self-propagating oscillations in the electromagnetic field they aren't mystery balls of energy any more than any other particle is.

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Randywithout8as t1_j8jo36y wrote

I mean, to OP it seems like they're mystery balls. I don't feel "self-propogating oscillations in the electromagnetic field" is very helpful as an explanation... you can critize what I've put down, but maybe try improving on it rather than just listing the definition and feeling superior.

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platoprime t1_j8jo8wr wrote

Why not? Because you don't think they'd understand it? Because you can't explain it?

I'm struggling to imagine a good justification for, well, misinformation.

> but maybe try improving on it rather than just listing the definition and feeling superior.

I can definitely explain it better if you like.

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Laetitian t1_j8jo4vh wrote

"In the electromagnetic field" probably just takes it from "mystery balls of energy" to "balls inside a mystery ether" for someone who doesn't understand the subject properly.

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platoprime t1_j8k1nii wrote

The solution to that is to explain fields not lie about the nature of photons.

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iam666 t1_j8lr1nb wrote

This answer, while not incorrect, doesn’t answer OP’s question. OP basically asked “how do we know light has a wavelength” and your answer says “it has a wavelength”.

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Randywithout8as t1_j8ludfk wrote

You might be right. I interpreted it as "when you measure a photon's wavelength, what is actually being measured?" Typically it is the energy of the photon that is being measured. Then the wavelength is calculated. I may have been too literal.

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