
The entropy is

By differentiation

By switching r and s

By addition

s >
r
s) >
ln(
t)This yields the SL-IV form of the second law:
0 The system evolves towards a unique equilibrium state. This state is easily found from
= 0
which shows that in the equilibrium state
r is constant, independent of r.
Author Per Stoltze stoltze@fysik.dtu.dk