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Velocity of light and temperature of medium

  1. Mar 7, 2008 #1
    do velocity of light changes in hot or cold medium(air or water)....if it changes,wat is the reason for that change....wat effect the temperature of medium has on velocity of light?
  2. jcsd
  3. Mar 7, 2008 #2


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    The temperature can affect the index of refraction, but I expect that the effect is too small to have been measured.
  4. Mar 7, 2008 #3


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    I guess it depends on what one means by "light". The temperature dependence is definitely quite easy to see in the microwave regime, the permittivity changes a LOT for some materials which in turns affect e.g. the properties of waveguides.
    Presumably it should be possible to see this effect in the optical regime using e.g. an interferometer, but i guess it would be difficult to distinguish from other effects such as thermal expansion of the resonator itself.
  5. Mar 7, 2008 #4


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    The temperature effect is extremely important certain measurements, such as the recently published result from the Auger Observatory collaboration. It makes a lot of difference what the air temperature is when you're trying to collect the cerenkov light that these high energy particles are making as they go through the air. That's why they sample the air temperature often not just throughout the year, but in a day as well.

  6. Mar 7, 2008 #5
    are there any relation between temperature of medium and velocity of light ...i mean any expression or formula...
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