> On Sep 19, 12:42 pm, dedanoe gmail.com> wrote:

>> assume light travels from in.vacuum to in.glass and back again
>> in.vacuum: its speed will deccelerate from c to v and agian accelerate
>> from v to c.

>
> Wrong.
>

>> how do you explian the acceleration?

>
> There is no acceleration.
>

>> i mean does light
>> behave like p-mobile with renewable energy or so?

>
> Light travels at c in a vacuum. That includes the vacuum between
> atoms in matter.
>
> Light traveling "through" an atom is absorbed, and then normally re-
> emitted at exactly the same polarization, speed (c) and frequency,
> with a slight time delay due to interactions with the electromagnetic
> fields within the atom.
>
> For details see any comprehensive text on Special Relativity. Also
> research "polarizability" and the dielectric constant, as colligative
> properties of matter.
>
> A good text on the theory of the complex refractive index may also be
> helpful.
>
> Tom Davidson
> Richmond, VA