Does the wavelength change when light passes through glass?

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Discussion Overview

The discussion centers around the behavior of light as it passes through different media, specifically focusing on whether the wavelength of light changes when it transitions from air into glass and subsequently into other materials. Participants explore concepts related to light speed, frequency, and the perception of color in relation to the refractive index of materials.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that when light enters glass, its speed decreases due to the refractive index, suggesting that the wavelength must change while the frequency remains constant.
  • Another participant agrees that the wavelength changes and mentions that the light reaching the retina corresponds to the medium inside the eye.
  • A participant questions the perception of color when light from a ruby laser enters a diamond, asking whether it retains its ruby color or changes.
  • There is a discussion about whether the eye perceives frequency or wavelength, with one participant asserting that color is determined by frequency due to the relationship between energy and frequency.
  • Concerns are raised about how sandwiching films between glass might affect their sensitivity to color, with varying opinions on whether this effect is significant.
  • Another participant introduces the idea that the active grains in films may not be affected by the glass unless they are within a certain wavelength range.

Areas of Agreement / Disagreement

Participants express differing views on the implications of wavelength and frequency changes, particularly regarding the perception of color and the effects of different media on light properties. There is no consensus on the significance of these changes or their practical implications.

Contextual Notes

Some claims about the interaction of light with materials depend on specific definitions of color and the properties of the media involved, which remain unresolved in the discussion.

Who May Find This Useful

This discussion may be of interest to those studying optics, color perception, and the design of optical devices, as well as individuals curious about the behavior of light in different media.

rayjohn01
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I have a light ray traveling through air at 'c' , it then enters some ordinary glass say mu=1.5 , it slows down by mu. --- no problem.
According to the normal equation v = f . lambda , (velocity , frequency , wavelength) ,
'v' has slowed down from 'c' to 'c' / mu therefore the RHS must change

But what changes ?? 1.5 is a LOT.
if glass is a linear medium there seems no reason for 'f' to change , so it would appear that Lambda must .
when the ray exits the glass it changes back so what we see is what went in.
But what about the eye where the ray strikes the retina do we see an altered lambda different from the air ??
Ray
 
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You are correct. What changes is the wavelength. The wavelengths of the light that reaches your retina are those corresponding to the humor vitreous, that fills your eyeballs.
 
rayjohn01 said:
But what about the eye where the ray strikes the retina do we see an altered lambda different from the air ??

Yes we do. Another fun fact of physics (that, after all has been said, doesn't change much in our daily lives).
 
yes -- but

You are right Gonz , it is hardly Earth shattering , and probably very old science -- so answer this -- if a ruby Laser enters a diamond then what is the color ( physical sense) of it inside the diamond -- did you think it was ruby ? or what did you think ?
The color of the diamond (as seen ) is due to what ?
If I sandwich a film between glass does it change it's sensitivity to color ?
if so why and if not why.
Does the eye see -- frequency or wavelength - if the first then the ray entering the eye -- if the second the ray in the eye ?
The eye resolution is NOT due to the entering ray -- but the inside ray
which is 34% smaller .
Such questions are not Earth shattereing but actually effect how we design things .
Actually you cannot say so quickly that it is the Vitreous Humor unless the rods and cones are actually embedded in this and indeed any media prior to the destruction of the light wave at atomic absorbsion .

Ray
 
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rayjohn01 said:
You are right Gonz , it is hardly Earth shattering , and probably very old science -- so answer this -- if a ruby Laser enters a diamond then what is the color ( physical sense) of it inside the diamond
-- did you think it was ruby ? or what did you think ?

Our retina cells (and whatever chemical absorption that goes on in there) are affected by photon energy E = hf = hv/lambda, so strictly speaking "colour" is determined by frequency, more than wavelength. So suppose we immersed a "waterproof photodiode detector" in water or alcool, which has n > 1, I believe it would behave as would in air with the Ruby frequency.

rayjohn01 said:
If I sandwich a film between glass does it change it's sensitivity to color ?
if so why and if not why.

As far as I know, it doesn't (unless it heats up, or allows internal reflection and some nonlinear effect happens, depending on what film you use).

rayjohn01 said:
Such questions are not Earth shattereing but actually effect how we design things .

Not Earth shattering for normally-sighted people, but I agree it can matter for design, maybe even for some optometrist researchers.
 
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I think on the film you are mostly correct , but not for stated reasons , the active grains are already embedded within a media of it's own refractive index and therefore do not careabout the glass except that is for grains which are within a wavelength of the light within either media -- they maybe schitzophrenic .
Ray.
 
That makes a lot of sense. My "stated reasons" (in parenthesis) were simply rough examples of how sandwiching between glass might affect properties of some films. I still think grain activity (absorption) is determined by frequency.
 

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