Chapter 6: Motion of charge particle in Electric & Magnetic fields

Example 6.1.1, Page number 6-6

In [6]:
import math

#Variable declaration
m = 9.1*10**-31         #mass of electron(kg)
v = 2.5*10**6           #velocity of electron(m/s)
theta = 30*math.pi/180  #angle(degrees)
B = 0.94*10**-4         #field strength(Wb/m^2)
e = 1.6*10**-19         #electron charge(C)

#Calculations
r = (m*v*math.sin(theta))/(B*e)

l = (5*v*math.cos(theta)*2*math.pi*m)/(B*e)

#Results
print "Radius =",round(r/1e-3,2),"mm"
print "Distance covered =",round(l,3),"m"

Radius = 75.63 mm
Distance covered = 4.115 m

Example 6.1.2, Page number 6-7

In [9]:
import math

#Variable declaration
m = 9.1*10**-31         #mass of electron(kg)
v = 3*10**7             #velocity of electron(m/s)
theta = 45*math.pi/180  #angle(degrees)
B = 0.23*10**-4         #field strength(Wb/m^2)
e = 1.6*10**-19         #electron charge(C)

#Calculations
r = (m*v*math.sin(theta))/(B*e)

l = (v*math.cos(theta)*2*math.pi*m)/(B*e)

#Results
print "Radius =",round(r,2),"m"
print "Distance covered =",round(l,3),"m"
#Calculation mistakes in the textbook

Radius = 5.25 m
Distance covered = 32.959 m

Example 6.1.3, Page number 6-7

In [11]:
#Variable declaration
y = 1.5         #displacement(cm)
d = 0.42        #distance(cm)
Va = 1.6*10**3  #anode voltage(V)
D = 28          #cm
l = 1.8         #length of plates(cm)

#Calculation
V = (2*y*d*Va)/(D*l)
Vin = V/6

#Result
print "Input voltage =",round(Vin,2),"V"

Input voltage = 6.67 V

Example 6.5.1, Page number 6-16

In [13]:
#Variable declaration
da = 0.8    #minor axis(cm)
db = 2      #major axis(cm)

#Calculation
ps = math.degrees(math.asin(da/db))

#Result
print "Phase shift =",round(ps,2),"degrees"

Phase shift = 23.58 degrees