#importing modules
import math
from __future__ import division
#Variable declaration
E=5.5; #energy(eV)
Ef=5; #fermi energy(eV)
p=1/100; #probability
e=1.6*10**-19; #charge(coulomb)
k=1.38*10**-23; #boltzmann constant
#Calculation
x=E-Ef; #difference in energy(eV)
y=math.log((1/p)-1);
T=x*e/(k*y); #temperature(K)
#Result
print "temperature is",round(T,1),"K"
print "answer given in the book is wrong"
#importing modules
import math
from __future__ import division
#Variable declaration
rho=970; #density(kg/m**3)
N=6.02*10**26; #avagadro number
A=23; #atomic weight(kg)
h=6.62*10**-34; #planks constant(Js)
m=9.1*10**-31; #mass(kg)
e=1.6*10**-19; #charge(coulomb)
#Calculation
n=rho*N/A; #number of atoms per m**3
EF=(h**2/(8*m))*((3*n/math.pi)**(2/3)); #fermi energy(J)
EF=EF/e; #fermi energy(eV)
#Result
print "fermi energy is",round(EF,2),"eV"