Problems and Solutions on Thermodynamics and Statistical Mechanics

(Ann) #1
Statistical Physics 275

Solution:


p = - (g) , where F is the free energy, F = E - TS. When
T
T = 0 K, F = E, and


p=-(g) T.


2
Using pV = -El we have
3


or


p=-(g)T=-[-.-(fpV)]T=-;[V(g)T+P] a ,


5

1 av 3
Hence K. = --
(-)

= - (T = 0 K).
ap T 5P
At T = 0 K,
h2k2
d3k-
2E 2 V
3V 3V (2~)~ /,,,, 2m

p= - = -.2.-


we obtain

For an ideal gas, the energy of a particle is
h2 k2
2m
&(k) = -.

Thus
h2 k;
2m

&F=-.

Therefore,
2
5
p= -n.&F, (T= 0 K) ,
and
3
K.= -. (T=OK)
2n&F
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