sci.physics.research

Agreed. Sorry me previous post was vague. unintentionally :(
For most systems, say the ideal classical gas, if some more particles
are introduced into the (isolated) system
then the increase in entropy depends on the number of particles
introduced and also on the total energy added via these particles. For
photons, it doesnt matter how many photons one introduces into the
system, all that matters is the energy added. Moreover, the entropy/
is a constant independent of temperature or any
other physical parameters. its a pure number!
I think its strange. Is it just because the chemical potential is
zero?
THanks,
Goombaj

. I hope this time I've been more precise.

Peter wrote:
> On 27 Aug., 19:11, Igor Khavkine wrote:
>
> > On 2007-08-26, goom...@ wrote:
> > > Is the photon entropy independent of its frequency? does it remain
> > > constant? I am trying to work out the photon gas entropy using such a
> > > postulate. Is this well justified? Please cite sources wherever
> > > possible
>
> > Entropy is not a property of a particle, it is a statistical property of
> > ensembles of particles (or other things).
>
> This is the point. Consequently, the entropy does not depend on the
> energy of the individual particles, but of the set (spectrum) of
> energies they can assume, see Einstein, 'Specific heat of solids...',
> 1907. I also would like to recommend you Einstein's 1905 paper, where
> he argues that a gas of photons behaves like a dilute gas of atoms.
>
> > ...Now, calculating the entropy of a photon gas can be a tricky thing. It
> > involves dealing with statistical mechanics of a relativistic system.
> > Here's another question to ponder. Do thermodynamic properties of a
> > photon gas depend on the number of photons in it? The question is
> > intentionally vague. :-)
>
> Thus, consider the chemical potential to find it out ;-)
>
> Best wishes,
> Peter