Please solve this wave-optics based question?
1 Answer
The condition will be
Explanation:
In the present interference problem with two coherent sources
the distance between the coherent sources is d
and the detector moves on a very big circle
so the place of detection can be taken as distance D from the sources
The condition for maxima ,
path diff = n.
here n=4 and
if one draws a perpendicular from the 2nd source(on the right )
to the line joining the 1st source(on the left) to 4th maxima then the path difference will be equal to
base of the triangle formed with theta as vertical angle and d as the hypotenuse
therefore the angular displacement from the central maxima of
the fourth bright spot can be written as
Sin
or
and D is much larger compared to d ,
the fringes can be taken on an arc of circle D.
The angular displacement of the detector will be same angle
as D is very large the radius drawn from the two coherent sources to the 4th maxima will turn through same angle
