# Chapter 37 Line Communication¶

## Example 37.1 Page no 1007¶

In [8]:
#Given
U=1.48
U2=1.45

#Calculation
import math
C=U2/U
C1=math.asin(C)*180/3.14

#Result
print"The critical angle for a light is",round(C1,1),"degree"

The critical angle for a light is 78.5 degree


## Example 37.2 Page no 1007¶

In [19]:
#Given
u=1.7
u2=1.5

#Calculation
import math
C=u2/u
A=math.asin(C)*180/3.14
I=math.sqrt(u**2-u2**2)
A1=math.asin(I)*180/3.14

#Result
print"The critical angle is",round(A,1),"degree"
print"The angle of acceptance is",round(A1,1),"degree"

The critical angle is 62.0 degree
The angle of acceptance is 53.2 degree


## Example 37.3 Page no 1007¶

In [49]:
#Given
u1=1.5
u2=1.3
L=30                            #m
c=3*10**8

#Calculation
import math
V=c/u1
t1=L/V
C=u2/u1
C1=math.asin(C)*180/3.14
x=L/C
t=x/V

#Result
print"(a) Time taken for light in axical mode is",t1*10**7,"*10**-7 s"
print"(b) Time taken for light in highest order mode is",round(t*10**7,2),"*10**-7 s"

(a) Time taken for light in axical mode is 1.5 *10**-7 s
(b) Time taken for light in highest order mode is 1.73 *10**-7 s


## Example 37.5 Page no 1007¶

In [54]:
#Given
a=0.5
b=50.0                              #Km

#Calculation
import math
A=10*math.log10(a)
B=A/b

#Result
print"Attenuation is", round(B,2),"dB/Km"

Attenuation is -0.06 dB/Km