#importing modules
import math
from __future__ import division
#Variable declaration
M=1.4; #magnetic field(T)
H=6.5*10**-4; #magnetic field(T)
#Calculation
chi=M/H;
mew_r=1+chi; #relative permeability of iron
#Result
print "relative permeability of iron is",int(mew_r)
print "answer given in the book is wrong"
#importing modules
import math
from __future__ import division
#Variable declaration
M=3300; #magnetic field(amp/m)
H=220; #magnetic field(amp/m)
#Calculation
chi=M/H;
mew_r=1+chi; #relative permeability
#Result
print "relative permeability is",int(mew_r)
#importing modules
import math
from __future__ import division
#Variable declaration
H=10**6; #magnetic field(amp/m)
chi=1.5*10**-3;
mew0=4*math.pi*10**-7;
#Calculation
M=chi*H; #magnetisation of material(A/m)
B=mew0*(M+H); #flux density(T)
#Result
print "magnetisation of material is",M/10**3,"*10**3 A/m"
print "flux density is",round(B,4),"T"
print "answer given in the book varies due to rounding off errors"
#importing modules
import math
from __future__ import division
#Variable declaration
H=10**4; #magnetic field(amp/m)
chi=3.7*10**-3;
mew0=4*math.pi*10**-7;
#Calculation
M=chi*H; #magnetisation of material(A/m)
B=mew0*(M+H); #flux density(T)
#Result
print "magnetisation of material is",M,"A/m"
print "flux density is",round(B,4),"wb/m**2"
#importing modules
import math
from __future__ import division
#Variable declaration
r=5*10**-2 #radius(m)
I=500*10**-3; #current(A)
#Calculation
A=2*math.pi*r**2;
mew_m=I*A; #magnetic moment(Am**2)
#Result
print "magnetic moment is",round(mew_m*10**3,3),"*10**-3 Am**2"
print "answer given in the book varies due to rounding off errors"
#importing modules
import math
from __future__ import division
#Variable declaration
r=5.29*10**-11; #radius(m)
B=2; #magnetic field(T)
e=1.602*10**-19; #charge(c)
m=9.108*10**-31; #mass(kg)
#Calculation
mew_ind=e**2*r**2*B/(4*m); #change in magnetic moment(Am**2)
#Result
print "change in magnetic moment is",round(mew_ind*10**29,3),"*10**-29 Am**2"
#importing modules
import math
from __future__ import division
#Variable declaration
chi1=2.8*10**-4; #susceptibility
T1=350; #temperature(K)
T2=300; #temperature(K)
#Calculation
chi2=chi1*T1/T2; #susceptibility
#Result
print "susceptibility is",round(chi2*10**4,3),"*10**-4"
#importing modules
import math
from __future__ import division
#Variable declaration
Bs=0.65; #magnetic induction(wb/m**2)
d=8906; #density(kg/m**3)
n=6.025*10**26; #avagadro number
mew0=4*math.pi*10**-7;
w=58.7; #atomic weight(kg)
#Calculation
N=d*n/w; #number of nickel atoms(per m**3)
mew_m=Bs/(N*mew0*9.27*10**-24); #magnetic moment(mewB)
#Result
print "magnetic moment is",round(mew_m,2),"mewB"
#importing modules
import math
from __future__ import division
#Variable declaration
mew=9.4*10**-24;
H=2; #magnetic field(weber/m**2)
k=1.38*10**-23; #boltzmann constant
#Calculation
T=2*mew*H/(math.log(2)*k); #temperature(K)
#Result
print "temperature is",round(T,1),"K"
#importing modules
import math
from __future__ import division
#Variable declaration
d=7.8*10**3; #density(kg/m**3)
n=6.025*10**26; #number of atoms
w=157.26; #atomic weight(kg)
mewm=9.27*10**-24;
mew=7.1*mewm;
mew0=4*math.pi*10**-7;
#Calculation
N=d*n/w; #number of atoms
mew_B=N*mew/10**3; #magnetic moment per gram(Am**2)
Bs=N*mew0*mew;
#Result
print "magnetic moment per gram",round(mew_B,3),"Am**2"
print "magnetic moment per gram is",round(Bs,4),"Wb/m**2"
print "answer given in the book varies due to rounding off errors"
#importing modules
import math
from __future__ import division
#Variable declaration
Tc=3.7; #temperature(K)
Hc0=0.0306; #critical field(T)
T=2; #temperature(K)
#Calculation
Hc2=Hc0*(1-(T/Tc)**2); #critical field(T)
#Result
print "critical field is",round(Hc2,5),"Tesla"
#importing modules
import math
from __future__ import division
#Variable declaration
Tc=7.18; #temperature(K)
H0=6.5*10**4; #critical field(T)
T=4.2; #temperature(K)
d=1*10**-3; #diameter(m)
#Calculation
Hc=H0*(1-(T/Tc)**2); #critical field(T)
ic=math.pi*d*Hc; #critical current(A)
#Result
print "critical current is",round(ic,2),"A"
print "answer given in the book is wrong"