Velocity of light and temperature of medium

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Discussion Overview

The discussion centers on the relationship between the velocity of light and the temperature of various media, such as air and water. Participants explore how temperature may influence the speed of light through changes in the medium's properties, particularly the index of refraction.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that temperature affects the index of refraction, which in turn could influence the velocity of light, although the effect may be too small to measure.
  • One participant notes that the temperature dependence of light is more pronounced in the microwave regime, where permittivity changes significantly for certain materials, affecting waveguide properties.
  • Another participant suggests that while it may be possible to observe temperature effects in the optical regime using interferometry, distinguishing these effects from other factors like thermal expansion could be challenging.
  • A participant emphasizes the importance of temperature effects in specific measurements, such as those conducted by the Auger Observatory, where air temperature significantly impacts the collection of Cherenkov light from high-energy particles.
  • There is a query about the existence of any expressions or formulas relating the temperature of a medium to the velocity of light.

Areas of Agreement / Disagreement

Participants express varying views on the significance and measurability of temperature's effect on the velocity of light, indicating that multiple competing perspectives remain without a clear consensus.

Contextual Notes

Participants acknowledge potential limitations in measuring the temperature effect on light velocity and the complexity of isolating this effect from other variables in experimental setups.

spidey
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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?
 
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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.
 
pam said:
but I expect that the effect is too small to have been measured.

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.
 
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.

Zz.
 
ZapperZ said:
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.

Zz.

are there any relation between temperature of medium and velocity of light ...i mean any expression or formula...
 

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