 # PROBLEM 4 # 
Standard formula used 
1/2 * m*v^2 = E_0 
 E = (h^2 / (8 * pi^2 * m)) * (3 * pi^2 * N/V)^(2/3) 

 Fermi energy is 7.035979 eV.
 Average energy is 4.221587 eV. 