if separation between the two slits is increased till fringes are observed then what will happen to angular separation of fringes

(my thought is here  fringes are not observed  and they are increasing till fringes show up ...so until then what will happen to angular width if we increase d-slit separation..does angular width increases or remains same

 

Asked by neetaspirantdoctor | 20th May, 2022, 03:57: PM

Expert Answer:

we know , we observe interference pattern if the following condition is satisfied
 
d sinθ = n λ
 
where d is distance between slits, θ is angular position of bright fringe , n is integer and λ is wavelength.
 
Angular position is obtained from above expression as
 
sinθ ≈ θ = ( n λ ) / d
 
We see that from above expression , angular position θ decreases as d increases for same n-th fringe

Answered by Thiyagarajan K | 21st May, 2022, 08:24: AM