# 10: Superconductivity¶

## Example number 10.1, Page number 224¶

In [1]:
#importing modules
import math
from __future__ import division

#Variable declaration
T=5;     #temperature(K)
Tc=7.2;   #critical temperature(K)
H0=6.5*10**3;   #critical magnetic field(A/m)

#Calculation
Hc=H0*(1-(T/Tc)**2);    #critical field(A/m)

#Result
print "critical field is",round(Hc/10**3,3),"*10**3 A/m"

critical field is 3.365 *10**3 A/m


## Example number 10.2, Page number 225¶

In [2]:
#importing modules
import math
from __future__ import division

#Variable declaration
T=2.5;     #temperature(K)
Tc=3.5;   #critical temperature(K)
H0=3.2*10**3;   #critical magnetic field(A/m)

#Calculation
Hc=H0*(1-(T/Tc)**2);    #critical field(A/m)

#Result
print "critical field is",round(Hc/10**3,3),"*10**3 A/m"

critical field is 1.567 *10**3 A/m


## Example number 10.3, Page number 225¶

In [6]:
#importing modules
import math
from __future__ import division

#Variable declaration
Hc=5*10**3;    #critical magnetic field(A/m)
T=6;     #temperature(K)
H0=2*10**4;   #critical magnetic field(A/m)

#Calculation
Tc=T/math.sqrt(1-(Hc/H0));     #critical temperature(K)

#Result
print "critical temperature is",round(Tc,3),"K"
print "answer given in the book is wrong"

critical temperature is 6.928 K
answer given in the book is wrong


## Example number 10.4, Page number 225¶

In [8]:
#importing modules
import math
from __future__ import division

#Variable declaration
Hc=2*10**3;    #critical magnetic field(A/m)

#Calculation
Ic=2*math.pi*r*Hc;     #critical current(amp)

#Result
print "critical current is",round(Ic,1),"amp"
print "answer in the book varies due to rounding off errors"

critical current is 251.3 amp
answer in the book varies due to rounding off errors


## Example number 10.5, Page number 225¶

In [9]:
#importing modules
import math
from __future__ import division

#Variable declaration
T1=5;     #temperature(K)
T2=5.1;     #temperature(K)
M1=199.5;   #isotopic mass(amu)

#Calculation
M2=M1*(T1/T2)**2;    #isotopic mass(amu)

#Result
print "isotopic mass is",round(M2,2),"amu"

isotopic mass is 191.75 amu


## Example number 10.6, Page number 226¶

In [12]:
#importing modules
import math
from __future__ import division

#Variable declaration
T=5;     #temperature(K)
Tc=8;   #critical temperature(K)
H0=5*10**4;   #critical magnetic field(A/m)

#Calculation
Hc=H0*(1-(T/Tc)**2);    #critical field(A/m)
Ic=2*math.pi*r*Hc;     #critical current(amp)

#Result
print "critical field is",round(Hc/10**4,4),"*10**4 A/m"
print "critical current is",round(Ic,3),"amp"
print "answer in the book varies due to rounding off errors"

critical field is 3.0469 *10**4 A/m
critical current is 287.161 amp
answer in the book varies due to rounding off errors


## Example number 10.7, Page number 226¶

In [13]:
#importing modules
import math
from __future__ import division

#Variable declaration
Tc1=4.185;     #critical temperature(K)
M1=199.5;   #isotopic mass(amu)
M2=203.4;   #isotopic mass(amu)

#Calculation
Tc2=Tc1*math.sqrt(M1/M2);      #critical temperature(K)

#Result
print "critical temperature is",round(Tc2,4),"K"

critical temperature is 4.1447 K


## Example number 10.8, Page number 226¶

In [14]:
#importing modules
import math
from __future__ import division

#Variable declaration
e=1.6*10**-19;    #charge(c)
h=6.626*10**-36;   #plank constant
V=8.5*10**-6;    #voltage(V)

#Calculation
new=2*e*V/h;    #frequency(Hz)

#Result
print "frequency is",round(new/10**11,3),"*10**11 Hz"

frequency is 4.105 *10**11 Hz


## Example number 10.9, Page number 227¶

In [15]:
#importing modules
import math
from __future__ import division

#Variable declaration
Tc1=5;     #critical temperature(K)
P1=1;   #pressure(mm)
P2=6;   #pressure(mm)

#Calculation
Tc2=Tc1*P2/P1;      #critical temperature(K)

#Result
print "critical temperature is",Tc2,"K"

critical temperature is 30.0 K


## Example number 10.10, Page number 227¶

In [16]:
#importing modules
import math
from __future__ import division

#Variable declaration
Hc=6*10**5;    #critical magnetic field(A/m)
Tc=8.7;     #critical temperature(K)
H0=3*10**6;   #critical magnetic field(A/m)

#Calculation
T=Tc*math.sqrt(1-(Hc/H0));     #maximum critical temperature(K)

#Result
print "maximum critical temperature is",round(T,3),"K"
print "answer given in the book is wrong"

maximum critical temperature is 7.782 K
answer given in the book is wrong