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Please could sum1 give me a suggestion here

  1. Sep 29, 2006 #1
    Please could sum1 give me a suggestion here!!

    Hi, i recently did an experiment whereby all the visble colours of white light are shone through a milky jar (ie milk and water meant to imitate fog!).

    Yellow shines through the greatest and they say(from articles where they explain why yellow liht is used in fog lamps) because it has the longest wavelength, thus its ability to diffract around the molecules is greater then those with shorter wavelengths.

    However , i thought red had the longest wavelength of visble light, so this is more likely to be able to diffract more effectively.

    However my final thought now is that, although red and orange may have longer wavelengths, and thus their difraction may be greater but therefore also more diffuse, spreading out more, so that the reading taken at the other side of the jar for intensity in lumens, will b less then yellow, since yellow wont be so diffuse, but still diffract to a great enough extent to register more then red/orange with more diffuse.....

    Would u agree with this final thinking .....??? or is there more to this i should know???

    Thanks Heaps!!! (if u got this far!!! ) thanks
  2. jcsd
  3. Sep 29, 2006 #2


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    Your milk bottle is a lens, badly formed, that is causing both refraction and diffraction problems (effects) to the light. You have chromatic aberration problems and diffraction problems in focusing to the "most visable" light, causing yellow to be, as in most short focal length lenses, the "circle of least confusion". Go to: http://en.wikipedia.org/wiki/Chromatic_Aberration and read about that and then click on "circle of least confusion" link on that page. Then go to this site to read about yellow in fog lights. These three sites should explain explain the yellow you see most easily.
  4. Sep 29, 2006 #3
    Last edited: Sep 29, 2006
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