The velocity of photon in media

1. Aug 8, 2012

azureth

what is the velocity of photon in media, c or c/n ?

2. Aug 8, 2012

Larsani

I would assume that would depend on the media. Correct me if I'm wrong, but I think I remember reading something about the speed of light through a bose-einstein condensate being on the order of 17m/s, maybe 21m/s. Either way, very slow. Glass, water, plastic I'm sure all have slightly different values for c, but no where near the tens of m/s like some materials.

3. Aug 8, 2012

azureth

Actually I am talking about common media with its refraction index given.

4. Aug 8, 2012

Larsani

That would be the sine of the angle wouldn't it?

Or more specifically $v_{2} = \frac{v_{1}sinθ_{2}}{sinθ_{1}}$

Last edited: Aug 8, 2012
5. Aug 8, 2012

sophiecentaur

You are making a lot of assumptions about the nature of photons. There is no reason to treat them as little bullets, speeding from place to place. The whole essence of QM is not to think of photons as existing 'anywhere' except when they are emitted and detected.

6. Aug 8, 2012

andrien

photons always move with speed c.the refractive index part just accounts for a phase shift for light.it does not mean that photon move at speed c/n.for further reference you can see feynman lectures vol.1('the origin of refractive index').

7. Aug 8, 2012

Thanks.

8. Aug 8, 2012

Drakkith

Staff Emeritus
I'm not quite sure what you are saying, but I was near certain that light does in fact move slower through a medium such as glass, with V=c/n.

9. Aug 8, 2012

Staff: Mentor

From the FAQ at the top of this forum: