Discuss the below:
Q1: (i) What are the main assumptions of the free electron model?
(ii) Give an example where the free electron model is in good agreement with experiment.
(iii) Give an example where the free electron model fails.
Q2: (i) How does the nearly free electron model improve on the free electron model?
(ii) Describe one of the successes of the nearly free electron model over the free electron model.
Q3:Calculate the mean free path in copper for which Kf, the k-vector of electrons at the Fermi energy is 1.35 10^10 m^-1, given that t=2.4x10^-14s