You should be able to answer these questions without too much difficulty after studying this TLP. If not, then you should go through it again!
For phonons, the normal modes
Using the assumptions in the Free electron model, how do crystal lattices affect electrons?
Umklapp scattering is:
According to the Wiedemann-Franz law, which of the following is true?
Which of the following statements about electrical conduction in nearly pure materials are true?
Which of these is the correct order in terms of best to worst electrical conductivity (assumed pure materials) ?