Drude model of conductivity: For Cu metal we have Atomic density = natomic = 8.

Question

Drude model of conductivity: For Cu metal we have Atomic density = natomic = 8. 47 times 1028/m3; nearest neighbor distance between atoms = am = 2. 9 A Assume 1 free e'/atom, calculate the average time between collisions, tau at 4K and 300K. Calculate the average thermal velocity, vth, at 4K and 300K. Calculate the average mean free path, lmfp = vth. tau at 4K and 300K. We will see that when the Pauli principle is applied to e in solids that our expression for is too small. We will see that vth withPauli = 10 times vth at 300K and is approximately constant for T [1K, 500K]. With this value, recalculate the results of c).

Explanation / Answer

average thermal velocity u(thermal) = v(3kT/m) average mean free path Well, it's dependent on temperature and pressure, and thus, height. The mean free path for an air molecule at sea level assuming a standard atmosphere, and an average molecular radius of ~0.18nm, the mean free path is about 68nm using the equation l = 1/(sqrt(2)*n*s). CO2's mean free path is slightly smaller given a larger collision cross section s, but only by a few nanometers. n=N/V=p/(kT) is the number of molecules per unit volume s = pi*(2*r)^2 is the collision cross section

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