# 4: Fiber Optics¶

## Example number 4.1, Page number 126¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
mew = 1.5;          #refractive angle for glass

#Calculation
ip = ip*180/math.pi;         #brewster's angle(degree)
ip = math.ceil(ip*100)/100;   #rounding off to 2 decimals
r = 90-ip;        #angle of refraction(degree)
r = math.ceil(r*10)/10;   #rounding off to 1 decimal

#Result
print "brewster's angle is",ip,"degrees"
print "angle of refraction is",r,"degrees"

brewster's angle is 56.31 degrees
angle of refraction is 33.7 degrees


## Example number 4.2, Page number 126¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
mew0 = 1.658;         #refractive index of calcite
mew_layer = 1.550;    #refractive index of canada balsam

#Calculation
sinC = mew_layer/mew0;
C = C*180/math.pi;           #critical angle(degrees)
i = 90-C;              #maximum possible inclination(degrees)
i = math.ceil(i*10)/10;   #rounding off to 1 decimal

#Result
print "maximum possible inclination is",i,"degrees"

maximum possible inclination is 20.8 degrees


## Example number 4.3, Page number 126¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
mew0 = 1.544;         #refractive index of calcite
mewe = 1.533;    #refractive index of canada balsam
lamda = 5000;          #wavelength(angstrom)

#Calculation
lamda = lamda*10**-10;         #wavelength(m)
t = lamda/(2*(mew0-mewe));         #thickness of half wave plate(m)
t = t*10**4;
t = math.ceil(t*10**4)/10**4;   #rounding off to 4 decimals

#Result
print "thickness of half wave plate is",t,"*10**-4 m"

thickness of half wave plate is 0.2273 *10**-4 m


## Example number 4.4, Page number 126¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
l = 20;        #length of glass tube(cm)
theta = 26.2;       #polarisation angle(degrees)
s = 20;          #weight of sugar(gm)
w = 100;        #quantity of water(ml)

#Calculation
l = l/10;         #length of glass tube(dm)
C = s/w;          #concentration(gm/cc)
S = theta/(l*C);        #specific rotation(degrees per dm per(gm/cc))

#Result
print "specific rotation of sugar is",S,"degrees per dm per(gm/cc)"

specific rotation of sugar is 65.5 degrees per dm per(gm/cc)