#Chapter 19,Example 1,page 665
#Determine the sepration between the particles
# Based on the equations 19.6, 19.7, 19.8, 19.9 and 19.10
E = 8*10**5 # V/m
qm = 10*10**-6 # C/kg, qm = q/m
y = -1 # m
t = (1*2/9.8)
x = 1./2.*qm*E*t
print"\n The seperation between the particles = m",round(2*x,3)
# Answers may vary due to round off error
#Chapter 19,Example 2,page 667
#Determine the pumping pressure
p0 = 30*10**-3 # C/m**3
V = 30*10**3 # V
P = p0*V
print"\n The pumping pressure P = N/m**2",P
# Answers may vary due to round off error
#Chapter 19,Example 4,page 670
#Determine the vertical displacement of the drop
d = 0.03*10**-3 # m
p = 2000 # kg/m**3
q = 100*10**-15 # C
V0 = 3500. # V
d2 = 2*10**-3 # m
L1 = 15*10**-3 # m
L2 = 12*10**-3 # m
Vz = 25. # m/s
from math import pi
m = 4./3.*pi*(1./2.*d)**3*p
t0 = L1/Vz
Vx0 = q*V0*t0/(m*d2)
x0 = 1./2.*Vx0*t0
t1 = (L1+L2)/Vz
x1 = x0+Vx0*(t1-t0)
print"\n The vertical displacement of the drop = m",round(x1,4)
# Answers may vary due to round off error
#Chapter 19,Example 5,page 672
#Determine the electric stress and charge density
a = 25*10**-6 # m
b = 75*10**-6 # m
Er = 2.8
ps = 25*10**-6 # C/m**3
E0 = 8.84*10**-12
Ea = (b*ps)/(ps*E0+b*Er*E0)
Eb = (a*ps)/(ps*E0+b*Er*E0) # the negative noation is removed to obtain positive answer as in the book
psc = E0*Eb
print"\n Ea = V/m",Ea
print"\n Eb = V/m",Eb
print"\n Charge density = C/m**2",psc
# Answers may vary due to round off error
#Chapter 19,Example 6,page 675
#Determine the current density
E0 = 8.84*10**-12
Us = 1.5*10**-3*10**-4
V = 100
d3 = 10**-6 # d**3
J = 4*E0*Us*V**2/d3
print"\n Current density = A/m**2",J
# Answer may vary due to round off error
#Chapter 19,Example 7,page 676
#Determine the thickness of dust layer
Edb = 3*10**6
E0 = 8.84*10**-12
p0 = 15*10**-3
d = Edb*E0/p0
print"\n Thickness of the dust layer = m",round(d,5)
# Answers may vary due to round off errors
#Chapter 19,Example 8,page 676
#Determine the velocity of the ejected ions and propolsion force
from math import sqrt
mi = 133*1.67*10**-27 # kg
qi = 1.6*10**-19 # C
Va = 3500 # V
I = 0.2 # A
vi = sqrt(2*qi*Va/mi)
F = vi*mi*I/qi
print"\n Ion velocity = m/s",vi
print"\n Populsion force = N",F
# Answers may vary due to round off errors
#Chapter 19,Example 9,page 677
#Determine the position of the particle
V = 120*10**3 # applied voltage in V
d = 0.6 # space b/w the plates in m
vd = 1.2 # vertical dimention in m
qm = 10*10**-6 # charge to mass C/kg
y = 4.9
from math import sqrt
t0 = sqrt(vd/y)
# based on eq 19.51 and 19.52
dx2 = qm*V/d
x = t0**2
print"\n Velocity = m/s2",dx2
print"\n Position of the particle = m",round(x,2)
# Answer may vary due to round off error
#Chapter 19,Example 10,page 679
#Determine the minimum voltage required for gnerating drops witha charge of 50 pC per drop
from math import pi,log
q = 50*10**-12
a = 25*10**-6
b = 750*10**-6
E0 = 8.84*10**-12
r = 50*10**-6
V = (3*q*b**2*log(b/a))/(7*pi*E0*r**3)
print"\n The minimum voltage required for gnerating drops witha charge of 50 pC per drop = kV",round(V*10**-6,2)
# Answers may vary due to round off error