Optics Question 1101
Question: In Young’s double slit experiment, angular width of fringes is 0.20o for sodium light of wavelength 5890 Å. If complete system is dipped in water, then angular width of fringes becomes
[RPET 1997]
Options:
A) 0.11o
B) 0.15o
C) 0.22o
D) 0.30o
Show Answer
Answer:
Correct Answer: B
Solution:
Angular fringe width $ \theta =\frac{\lambda }{d}\Rightarrow \theta \propto \lambda $
$ {\lambda _{w}}=\frac{{\lambda _{a}}}{{\mu _{w}}} $ So $ {\theta _{w}}=\frac{{\theta _{\text{air}}}}{{\mu _{\text{w}}}} $
$ =\frac{0.20}{\frac{4}{3}}=0.15{}^\circ $
