14: Superconductivity

Example number 14.1, Page number 272

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

#Variable declaration
Bc0=0.0305;    #critical field(T)
T=2;   #temperature(K)
Tc=3.722;   #critical temperature(K)
r=2*10**-3;  #diameter(m)
mew0=4*math.pi*10**-7;   #magnetic permeability

#Calculation
BcT=Bc0*(1-(T/Tc)**2);   #critical field(T)
Ic=2*math.pi*r*BcT/mew0;   #current(A)

#Result
print "current is",round(Ic,1),"A"

current is 216.9 A

Example number 14.2, Page number 274

In [7]:
#importing modules
import math
from __future__ import division

#Variable declaration
lamda0=37;   #london penetration depth(nm)
T=5.2;    #temperature(K)
Tc=7.193;   #critical temperature(K)

#Calculation
a=1-(T/Tc)**4;
lamdaT=lamda0*(a**(-1/2));   #penetration depth of lead(nm)

#Result
print "penetration depth of lead is",round(lamdaT,3),"nm"

penetration depth of lead is 43.398 nm