# Chapter 14: Solids - Superconductors and Magnetic Properties¶

## Example 14.1, Page 489¶

In [1]:
#Calculations&Results
#Part a
k=1.4*10**-23#in J/K
Te=4.2#in K
eg=3*k*Te
print "The gap energy is  %.1e  J"%eg
h=6.63*10**-34#in j-s
c=3*10**8#m/s

#Part b
lamda=(h*c)/eg
print "The wavelength is  %.1e  m"%lamda

The gap energy is  1.8e-22  J
The wavelength is  1.1e-03  m


## Example 14.3, Page 496¶

In [2]:
import math

#Variable declaration
u=9.3*10**-24#in Tesla
B=1#in Tesla
Eb=u*B*6.24150934*10**18
T=300#in K
k=8.6*10**-5#ev/k

#Calculations&Results
x=k*T
s=(Eb/x)*100
#Part a
print "The percentage is  %.1f"%s

#Part b
n=2.0*10**28#/m3
k=1.38*10**-23#in J/k
uo=4*math.pi*10**-7#T-m/amp
con=(uo*n*u*u)/(k*T)
print "The number of unpaired electrons is  %.1e"%con

The percentage is  0.2
The number of unpaired electrons is  5.3e-04


## Example 14.4, Page 498¶

In [3]:
import math

#Variable declaration
uo=4*math.pi*10**-7#T-m/amp
u=2.2*9.3*10**-24#in Tesla
x=3*10**-10#in m

#Calculations&Results
E=(uo*u*u)/(2*math.pi*x**3)
print "The Energy required  is  %.1e Joule"%E
k=1.38*10**-23#in J/k
T=E/k
print "The temperature  is  %.2f K"%T

The Energy required  is  3.1e-24 Joule
The temperature  is  0.22 K