Although the classical electron gas model does predict Ohm’s law, we see
from Example 12.1 that it results in conductivity values that differ from
Worse yet, the measured resistivity
of most metals is found to be proportional to the absolute temperature (see
Fig. 12.13), yet the classical electron gas model predicts a much weaker dependence
of
on T. From Equation 12.16 we see that the classical model incorrectly
predicts that resistivity should be proportional to the square root of
the absolute temperature. In Section 12.3 we will give a different model
of electron scattering, which explains the observed linear dependence of
on
T at high temperatures.
Classical Free Electron Theory