Chapter 20 Free electron theory

Example 20.1 Page no 191

In [12]:
#Given
a=0.971*10**3               #Kg/m**3
w=22.99
N0=6*10**26
m=9.1*10**-31                #Kg
h=6.626*10**-34                 #J-s

#Calculation
import math
N=(N0*a)/w
Ef=(h/(8*m))*((3*N)/math.pi)**0.66

#Result
print"Fermi energy is", round(Ef*10**-14,0)*10**-19,"J"

Fermi energy is 5e-19 J

Example 20.2 Page no 192

In [18]:
#Given
a=10**-10                 #m
m=9.1*10**-31               #Kg
h=6.626*10**-34                #J-s

#Calculation
E=3*h**2/(8*m*a**2)

#Result
print"Energy difference is", round(E*10**17,3)*10**-17,"J"

Energy difference is 1.809e-17 J

Example 20.3 Page no 192

In [23]:
#Given
x=1.39
K=0.025
Ef=3.2

#Calculation
E=x*K
E1=E+Ef

#Result
print"Energy at 300 K is", round(E1,3),"ev"

Energy at 300 K is 3.235 ev