1 Topic by William (edited by William 2025-07-07 18:23:33)

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Topic: Light travelling in glass

There is a very nice image in the following thread.

A Lesson in Light Frequencies and Wavelengths

https://forum.affinity.serif.com/index. … avelengths

This got me thinking.

https://en.wikipedia.org/wiki/Speed_of_light

As the speed of light in glass is slower than in vacuum, I am wondering what is the situation about frequency and wavelength of the light while it is travelling through glass, such as in a lens?

I have never known any mention of that in courses in optics and I have not seen it mentioned in books on optics.

  • Alfred
  • Alfred
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Re: Light travelling in glass

Thanks to dispersion, the speed of a wave depends on its frequency, so the speed of light through glass is different for each colour. A prism gives us the classic example of dispersion.

The frequency of the wave will be affected by the density and temperature of the medium through which it is travelling. A denser or colder medium will lower the frequency.

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