Re: Quasistatic conditions

["Carl E. Mungan" <mungan@USNA.EDU>]

Pentcho wrote:

>      The fact that a system is in equilibrium
> all along does not guarantee that the change it undergoes is
> quasistatic in the above sense. We can imagine a system
> thermally isolated from HOTTER surroundings but still a thin
> wire connects them so that the temperature of the system
> increases very slowly. The system is in equilibrium (passes
> through a succession of equilibrium states) but....what
> type of process is this????
>     It is extremely important for us to answer this question.
> Classically, the entropy is defined through dS=dQrev/T, but the
> subscript "rev" may mean, according to textbooks, two things.
> Either the system just passes through a succession of
> equilibrium states, or the system passes through a succession
> of equilibrium states but, in addition, exchanges heat with
> the surroundings ONLY WHEN SYSTEM AND SURROUNDINGS ARE OF THE
> SAME TEMPERATURE.

Interesting question.

But have you considered the possibility that there is a temperature
gradient along the wire so that each "mesoscopic portion" (in the
sense discussed by David) of the materials involved are in contact
with adjacent mesoscopic portions at only very slightly higher or
lower temperatures? Isn't this implied in the fact that the wire is
"thin"? Carl
--
Carl E. Mungan, Asst. Prof. of Physics  410-293-6680 (O) -3729 (F)
      U.S. Naval Academy, Stop 9C, Annapolis, MD 21402-5040
mailto:mungan@usna.edu       http://usna.edu/Users/physics/mungan/