Chapter 10:Inductance

Problem no:10.1, Page no:115

In [1]:
from __future__ import division

#Cal of average self-induced emf

#Initialization

L=25                        #Inductance in mH

del_I=0.2                   #Current in A

del_t=0.01                  #Time in s

#Calculation

L=L/1000                    #Inductance in H

V=L*(del_I/del_t)

print "V=",V,"V"

V= 0.5 V

Problem no:10.3, Page no:116

In [1]:
from __future__ import division

#Cal of inductance

#Initialization

N=500                       #No. of Turns

mu_o=1.26E-6                #Magnetic permeability of solenoid in air

A=20                        #Area in cm^2

l=10                        #Length in cm



#calculation

l=10/100                    #convert length in m

A=20/10000                  #Convert area in m^2

L= ((mu_o)*(N*N)*(A))/(l)   #Formula for inductance of solenoid

L=L*1000                    #convert inductance in mH

print "L=",L,"mH"

L= 6.3 mH

Problem no:10.4, Page no:116

In [2]:
from __future__ import division

import math

#Cal of turns of wire

#Initialization

L=0.178                      #Inductance in mH

l=20                         #Length of solenoid in cm

d=2                          #Diameter in cm

mu_o=1.26E-6                 #magnetic permeability in air

#Calculation

L=L/1000                     #Convert Inductance in H

l=l/100                      #Convert Length in m

d=2/100                      #Convert diameter in m

r=d/2                        #Cal of radius

A=(math.pi)*(r**2)           #Cal of Area in m^2

N=math.sqrt((L*l)/(mu_o*A))  #Calculating No.of Turns

print "N= ",int(round(N)),"turns"

N=  300 turns

Problem no:10.5, Page no:116

In [3]:
from __future__ import division

import math

#Cal of Inductance

#Initialization

D=5                          #Diameter in cm

A=1                          #Cross-sectional area in cm^&2

mu_o=1.26E-6                 #Magnetic permeability in air

mu=400*mu_o                  #Permeability of iron given

N=1000                       #No. of turns

#Calculation

l=math.pi*(D/100)            #Calculating length in m

A=A/10000                    #Convert Area in m^2

L=(mu*(N**2)*A)/(l)          #inductance Formula

print "L=",round(L,2),"H"

L= 0.32 H

Problem no:10.6, Page no:117

In [7]:
from __future__ import division

#Cal of magnetic potential energy

#initialization

L=20                          #inductance in mH

I=0.2                         #Current in A

#Calculation

L=L/1000                      #Convert Inductance in H

W=(1/2)*(L*I**2)              #Formula for energy in current-carrying conductor

print "W=",'%4.0E' % W,"J"

W= 4E-04 J

Problem no:10.7, Page no:117

In [4]:
from __future__ import division

import math

#Cal of Current

#initialization

L=20                     #Inductance in mH

W=1                      #Energy in J

#Calculation

L=L/1000                 #convert Inductance in H

I=math.sqrt((2*W)/L)

print "I=",int(I),"A"

I= 10 A

Problem no:10.8, Page no:119

In [7]:
from __future__ import division


#Cal of Current

#Initialization

L=0.1                       #Inductance in Henry

V=12                        #Voltage in volts

R=20                        #Resistance in Ohm

I=V/R

print "(a)  del_I/del_t =",int(V/L),"A/s"

print "(b)  As the current increases,its rate of change del_I/del_t decreases."

print "(c)  I=",I,"A"

(a)  del_I/del_t = 120 A/s
(b)  As the current increases,its rate of change del_I/del_t decreases.
(c)  I= 0.6 A