Optics Question 860
Question: Two light waves having the same wavelength $ \lambda $ in vacuum are in phase initially. Then the first ray travels a path of length $ L _{1} $ through a medium of refractive index $ {\mu _{1}} $ . The second ray travels a path of length $ L _{2} $ through a medium of refractive index $ {\mu _{2}} $ . The two waves are then combined to observe interference effects. The phase difference between the two, when they interfere, is
Options:
A) $ \frac{2\pi }{\lambda }(L _{1}-L _{2}) $
B) $ \frac{2\pi }{\lambda }({\mu _{1}}L _{1}-{\mu _{2}}L _{2}) $
C) $ \frac{2\pi }{\lambda }({\mu _{2}}L _{1}-{\mu _{1}}L _{2}) $
D) $ \frac{2\pi }{\lambda }[ \frac{L _{1}}{{\mu _{1}}}-\frac{L _{2}}{{\mu _{2}}} ] $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Effective path difference is $ {\mu _{1}}L _{1}-{\mu _{2}}L _{2} $
