 Show that the claims made in the backbone text are actually true (for room temperature =
300 K). Use the following equations taken from the backbone 

 For the average velocity
v_{0} of a particle zooming around in the crystal: 
 
v_{0}  =  æ ç è
 3kT m  ö ÷ ø
 1/2 


  For the mean time t between scattering: 
 

  For the drift velocity v_{D} 
 

  For the minimal mean free path length l_{min} obtained for
v_{D} = 0: 
 

 Of course, you need numbers for the concentration
n of the free carriers and for the specific conductivity s 
  Since we are essentially considering metals, you
assume for a start that you have 1 free electron per atom if you want to find a number for n. Here
are a few data needed for the calculation: 
 
Atom  Density [kg ·
m^{–3}]  Atomic weight × 1,66 · 10^{–27}
kg  Conductivity
s × 10^{5} [W^{–1} ·
m^{–1}]  Conzentration Atoms n [m^{–3}]
???  Na  970  23  2.4   Cu  8.920  64  5.9   Au  19.300  197  4.5  

 You may run into some trouble with the dimensions.
Just look at conversions from, e.g. [eV] to [J], from W to V and
A, and at the relations beween Volt, Ampere, Watts and Joule. 

