//Example 16.6//

h=0.663*10^-33;//J s //Planck's constant
c=0.300*10^9;//m/s //speed of light
Eg=1.47;//eV // energy gap for GaAs
a=6.242*10^18;//eV/J //1 Coulomb of charge
l=(h*c/Eg)*a
mprintf("l = %e m",l)
mprintf(" = 844nm (As 1nano = 10^-9)")