# Chapter 24 Superconductivity¶

## Example 24.1 Page no 289¶

In [36]:
#Given
H1=1.4*10**5                       #A/m
H2=4.2*10**5
T1=14                              #K
T2=13
Tc=14.5
H0=20.66*10**5                        #A/m
T=4.2

#Calculation
Hc=H0*(Tc**2-T**2)/Tc**2

#Result
print"Critical field is",round(Hc*10**-5,1),"*10**5 A/m"

Critical field is 18.9 *10**5 A/m


## Example 24.2 Page no 290¶

In [12]:
#Given
Tc1=4.185                          #K
M1=199.5
M2=203.4

#Calculation
import math
Tc2=Tc1*math.sqrt(M1)/math.sqrt(M2)

#Result
print"Critical temperature is",round(Tc2,2),"K"

Critical temperature is 4.14 K


## Example 24.3 Page no 290¶

In [26]:
#Given
T=4.2                           #K
H0=6.5*10**4                      #A/m
Tc=7.18
d=10**-3

#Calculation
Hc=H0*(Tc**2-T**2)/Tc**2
Jc=4*Hc/d

#Result
print"Critical current is", round(Jc*10**-8,3),"*10**8 A/m**2"

Critical current is 1.71 *10**8 A/m**2


## Example 24.4 Page no 291¶

In [35]:
#Given
w=750                         #A
T=3.5
Tc=4.12
h=6.02*10**26
a=13.55*10**3
M=200.6

#Calculation
import math
W=w*math.sqrt(1-(T/Tc)**4)
n0=h*a/M
ns=n0*(1-(T/Tc)**4)

#Result
print"Penetration is", round(ns*10**-28,2)*10**28,"/m**3"

Penetration is 1.95e+28 /m**3