# Chapter 11 Magnetic Effects Of Current And Magnetism¶

## Example 11.1 Page no 350¶

In [10]:
#Given
i=90                #A
a=1.5               #m
b=2
l=10**7

#Calculation
u=l*((b*i)/a)

#Result
print"Magnitude of the magnetic field is",u*10**-9,"10**-5","T"
print"Direction of the magnetic field is south"

Magnitude of the magnetic field is 1.2 10**-5 T
Direction of the magnetic field is south


## Example 11.2 Page no 350¶

In [16]:
#Given
I=3                  #A
a=0.15               #m
e=10**-7
b=2

#Calculation
Z=(e*b*I)/a

#Result
print"The magnitude of the magnetic field is",Z*10**6,"10**-6","T"

The magnitude of the magnetic field is 4.0 10**-6 T


## Example 11.4 Page no 351¶

In [38]:
#Given
l=10                     #A
a=0.05                   #cm
b=10**-7
a1=45                      #degree

#Calculation
import math
B=b*(l/a)*(math.sin(a1*3.14/180.0)+math.sin(a1*3.14/180.0))
B1=4*B

#Result
print"Magnetic field induction is",round(B1*10**4,2),"*10**-4 T"

Magnetic field induction is 1.13 *10**-4 T


## Example 11.5 Page no 351¶

In [44]:
#Given
n=10
a=0.08                          #m
l=2                             #A
v=10**-7

#Calculation
import math
B=(v*l*math.pi*n*l)/a

#Result
print"Magnitude of the magnetic field is", round(B*10**4,2),"*10**-4 T"
print"Direction of the field is vertically downward."

Magnitude of the magnetic field is 1.57 *10**-4 T
Direction of the field is vertically downward.


## Example 11.6 Page no 351¶

In [49]:
#Given
v=2.2*10**6                           #m/s
a=0.5*10**-10                          #m
e=1.6*10**-19
m=10**-7                                #N/a**2

#Calculation
import math
I=e*v/(2*math.pi*a)
B=m*2*math.pi*I/a

#Result
print"Magnetic field produced at the centre is", B,"T"

Magnetic field produced at the centre is 14.08 T


## Example 11.8 Page no 352¶

In [55]:
#Given
I=10                           #A
a=0.03                          #m
a1=360                         #degree
a2=90
a3=10**-7

#Calculation
import math
A=a1-a2
B=a3*I*3*math.pi/(a*2.0)

#Result
print"Magnitude of magnetic field is", round(B*10**4,2),"*10**-4 T"

Magnitude of magnetic field is 1.57 *10**-4 T


## Example 11.10 Page no 352¶

In [69]:
#Given
n=500
I=7                            #A
a=0.05                          #m
x=0.12                           #m
m=10**-7

#Calculation
import math
B=(2*math.pi*n*I*a**2)/(a**2+x**2)**1.5
B1=m*2*math.pi*n*I/a

#Result
print"(a) Magnetic field at the point on the axis is", round(B*10**-4,1),"*10**-3 tesla"
print"(b)Magnetic field at the centre of the coil is",round(B1*10**2,2),"*10**-2 tesla"

(a) Magnetic field at the point on the axis is 2.5 *10**-3 tesla
(b)Magnetic field at the centre of the coil is 4.4 *10**-2 tesla


## Example 11.13 Page no 353¶

In [75]:
#Given
B=2.52*10**-3                    #T
l=0.5                             #m
N=500

#Calculation
import math
n=N/l
I=B/(4*math.pi*10**-7*n)

#Result
print"Current in the solenoid is", round(I,0),"A"

Current in the solenoid is 2.0 A


## Example 11.14 Page no 353¶

In [80]:
#Given
I=5                     #A
l=2.0                       #m
n=1000
n1=5

#Calculation
N=n*n1
n2=N/l
B=4*math.pi*10**-7*n2*I

#Result
print"Magnetic field at the center is", round(B*10**2,2),"*10**-2 T"

Magnetic field at the center is 1.57 *10**-2 T


## Example 11.15 Page no 353¶

In [88]:
#Given
a=16.0*10**-2                      #m
n=20
I=16                              #A
b=10**-7
a1=10.0*10**-2
n1=25
I1=18

#Calculation
import math
B=b*2*math.pi*n*I/a
B1=b*2*math.pi*n1*I1/a1
B2=B1-B

#Result
print"Magnitude of the magnetic field is", round(B1*10**4,2),"*10**-4 T"
print"Direction is towards west"

Magnitude of the magnetic field is 28.27 *10**-4 T
Direction is towards west


## Example 11.18 Page no 355¶

In [105]:
#Given
l=11                     #A
s=3500
r1=25                     #cm
r2=26

#Calculation
import math
w=((r1+r2)/2.0)
l1=2*math.pi*w
n=s/l1
B=4*math.pi*10**-7*n*l

#Result
print"(a) Magnetic field outside the toroid is zero"
print"(b) Magnetic field inside the core is",round(B*10**4,2),"*10**-2 T"
print"(c) Magnetic field in the empty space is zero"

(a) Magnetic field outside the toroid is zero
(b) Magnetic field inside the core is 3.02 *10**-2 T
(c) Magnetic field in the empty space is zero