1. Demonstrate that the condition of avenging over many scattering events is met using the data and results of the above three problems.
2. From the drift velocity noise formulae, show that mobility fluctuation noise is not important compared with the thermal noise. Note that the mobility fluctuation noise has a white-noise (frequency independent) spectra up to a frequency of 1/2πτ then drop off as f-2 just like the thermal noise.