How do you measure Electromagnetic wavelength?

[g.lemaitre]

As we know EM waves have a wave length. Well, how do you measure them? I have the feeling there is a path from point A to point B and that path goes up and down at a regular rate and all photons travel along that wave-path and that they are no where else between A and B but on that path. But that view I have a feeling is incorrect. I think it's more probable that the photon occupies a probability space and that the line a photon is almost never here is a bit arbitrary and that is the length of the EM wave.

Also, I want to double check. I looked at wiki and I saw that the size of a photon is not listed prominently. Is that because they are bosons and can occupy the same space? If they can occupy the same space, then you can't measure their size.

 

[Drakkith]

First, forget everything you think you know about photons. It is wrong.
A photon is the quantized interaction of an electromagnetic wave. They do not have a size. They are not particles with mass that occupy space.

As for an EM wave, the wavelength is talking about how far the wave travels during one oscillation of its electric and magnetic field vectors. There is nothing moving up and down. The little squiggly lines you see representing photons is utterly incorrect. The EM wave travels outwards like ripples on the surface of a pond, only in three dimensions, not two. If you were to measure the EM wave as it travels, you could graph the changing electric and magnetic fields on a graph. This is what you normally see when you look at anything that shows a photon or an EM wave. The distance between any crest or trough is the wavelength.

 

[g.lemaitre]

Thanks.

 

[e.chaniotakis]

The simplest way to do it is by measuring interference patterns. Suppose that you have two identical sources of EM waves placed at a distance L between them.
Put your detector at some equidistant point from the two detectors . It will start ringing like crazy!
Then shift it aside , so that the distance from source 1 is r1 and from source 2 is r2.
When it starts ringing again like before , the difference between r1,r2 will be equal to the wavelength.

 

[sardar]

I can provide some information on how electromagnetic wavelength is measured. Electromagnetic waves, including light, radio waves, and X-rays, are a form of energy that travels through space in a wave-like pattern. The wavelength of an electromagnetic wave is the distance between two consecutive peaks or troughs in the wave.

To measure the wavelength of an electromagnetic wave, we use a device called a spectrometer. A spectrometer splits the electromagnetic wave into different wavelengths and measures the intensity of each wavelength. This information is then used to determine the wavelength of the original wave.

Another way to measure electromagnetic wavelength is by using diffraction grating. A diffraction grating is a tool that splits light into its component wavelengths, creating a spectrum. The spacing of the grating determines the resolution of the spectrum, allowing for precise measurements of the wavelength.

In terms of your thoughts on the path of an electromagnetic wave, it is true that photons travel in a wave-like pattern. However, the path is not a physical one, but rather a mathematical representation of the wave. As for the size of a photon, it is not listed prominently because it is a point particle and does not have a physical size. It is also a boson, which means it can occupy the same space as other photons, making its size difficult to measure.

In conclusion, the measurement of electromagnetic wavelength involves the use of specialized tools such as a spectrometer or diffraction grating. The path of an electromagnetic wave is a mathematical representation, and the size of a photon is not listed prominently because it is a point particle and can occupy the same space as other photons.