# Chapter 43 INTERFERENCE¶

## Example 43.1 Angular position of ﬁrst minimum¶

In [1]:
from __future__ import division
import math
m=1
lamda=546*10**-9
d=0.10*10**-3 #in m
sin_theta=((m-0.5)*lamda)/(d)
print("Sin theta = %.5f"%sin_theta)
theta=math.degrees(math.asin(sin_theta))
print("Angle in degree= %.5f"%theta)

Sin theta = 0.00273
Angle in degree= 0.15642


## Example 43.2 Linear distance¶

In [2]:
from __future__ import division
delta=546*10**-9  #in meter
D=20*10**-2     #in meter
d=0.10*10**-3  #in meter
delta_y=(delta*D)/d
print("Linear distance in meter= %.5f"%delta_y)

Linear distance in meter= 0.00109


## Example 43.4 Refraction¶

In [3]:
from __future__ import division
d=3200  #in A
n=1.33
for m in range(1,3):
lambda_max=(2*d*n)/(m+0.5)
lambda_min=(8500/m)
print("When m=",m)
print("Lambda_max=",lambda_max)
print("Lambda_min=",lambda_min)

When m= 1
Lambda_max= 5674.666666666667
Lambda_min= 8500.0
When m= 2
Lambda_max= 3404.8
Lambda_min= 4250.0


## Example 43.5 Refraction¶

In [4]:
from __future__ import division
lamda=5000 #in A
n=1.38
for m in range(0,4):
print("When m=",m)
d=((m+0.5)*lamda)/(2*n)
print("d in A=%.3f"%d)

When m= 0
d in A=905.797
When m= 1
d in A=2717.391
When m= 2
d in A=4528.986
When m= 3
d in A=6340.580