Optics Question 900
Question: In Young’s double-slit experiment, let A and B be the two slits. A thin film of thickness t and refractive index [i is placed in front of A. Let $ \beta =frings $ width. Then the central maxima will shift
Options:
A) toward A
B) toward B
C) by $ t(\mu -1)\frac{\beta }{\lambda } $
D) by $ \mu t\frac{\beta }{\lambda } $
Show Answer
Answer:
Correct Answer: A
Solution:
[a] For central maximum at P, $ \frac{xd}{D}=t(\mu -1) $ or $ x=t(\mu -1)\frac{D}{d} $ .
Now, $ \beta =\frac{D\lambda }{d} $
$ \therefore \frac{D}{d}=\frac{\beta }{\lambda } $ .
Hence, $ x=t(\mu -1)\frac{\beta }{\lambda } $
