Physics, asked by Vikasvishu143, 1 year ago

In interference pattern, using two coherent source of light; the fringe width is______
a) directly proportional to wavelength
b) inversly proportional to square of the wavelength
c) inversely proportional to wavelength
d) directly proportional to square of the wavelength

Answers

Answered by abhi178
5
Answer : (a) fringe width is directly proportional to wavelength .

Explanation :- as you know , fringe width is the separation between two consecutive bright or consecutive dark .
We know, for bright , yn = nλD/d ,
And for dark , yn = (2n-1)λD/d
Here, λ is wavelength of wave , d is the separation between slits and D is the separation between slit and screen.

Now, fringe width = Y₂ - Y₁ = 2λD/d - λD/d = λD/d [ when we take bright ]
also fringe width is same for dark = 3λD/2d - λD/2d = λD/d

Finally, fringe width = λD/d , hence, fringe width is directly proportional to wavelength.
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