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How to determine rarer & denser medium for light?

  1. Dec 4, 2009 #1
    How to determine rarer & denser medium for light?

    As i read in one book, it's written that denser medium & rarer medium for doesn't depend upon density.For eg. steam has less density than dry air but the steam is denser medium & dry air is rarer medium for light.Before this i used to think in simple way,substance that have high density is called denser medium & vice-versa.

    I even googled about it but i don't get any topic related with it.

    Hope you help.
  2. jcsd
  3. Dec 5, 2009 #2


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    Optical density can refer to either the absorption of light or the speed of light (i.e. index of refraction) in the medium. Usually this is clear from the context in a specific situation.

    So, a medium has a higher optical density if either it absorbs more light per length of material, or the speed of light is slower -- depending on which usage of optical density is being used.

  4. Dec 5, 2009 #3
  5. Dec 7, 2009 #4
    thanks for your suggestion.
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