# Speed of light in a different medium

1. May 24, 2008

### uq_civediv

a lot of transformation laws have c in them. the speed of light, however, depends on the medium ( $$c'$$ ) and is different from the $$c$$ in vaccuum.

so my question is, which one should i use in relativistic laws if the medium is , say, water with $$c' = \frac{c}{1.33}$$

of course one would say $$c$$, but in the $$w=\frac{u+v}{1+\frac{u v}{c^2}}$$ the speeds can get up to $$c$$, whereas in that medium they should never go faster than $$c'$$

or how should i apply relativistic laws in a specific medium ?

and the momentum of light $$\frac{E}{c}$$?

Last edited: May 24, 2008
2. May 24, 2008

### granpa

whereas in that medium they should never go faster than c'.