1. What is the qualitative variation of the resistivity of a metallic material with temperature ?
The resistivity decreases with decreasing temperature, initially linearly and then with a T5 variation.
3. In an ideal metal, what do you expect the resistivity to be at very low temperatures (nearly 0 K) ?
At low temperature, the resistivity becomes a constant. The residual resistivity depends on the impurity content in the metal.
3. In a real metal, on what factors does the residual resistivity (extrapolated zero-temperature resistivity) depend on ?
The residual resistivity depends on the impurity content in the metal.
4. Which are the various contributions to the heat capacity of a metallic material ?
There are two main contributions: one from the lattice vibrations (phonons) and the other from the electrons.
5. From measurements at low-temperatures, how can one determine the contributions to heat capacity from electrons and phonons ?
At low-temperatures, the electronic contribution is expected to vary linearly with temperature
while the phonon contribution has a
variation. By plotting C/T vs.
T2, one can obtain the intercept on the y-axis
and the slope of the data
.