// Chapter 2_Introduction to the quantum theory of solids
//Caption_Density of States
//Ex_3//page 63
m=9.11*(10^-31)      //mass of electron
h=6.625*(10^-34)
E=1.6*(10^-19)
N=((4*%pi*(2*m)^(1.5))/(h^3))*(E^(1.5))*(2/3)
printf('Density of states per unit volume with energies between 0 and 1 eV is %f states per unit vol \n',N)