Two light waves having the same wavelengths `lambda` in vacuum are in phase initially . Then the first wave travels a path `L_1` through a medium of refractive index `n_1` while the second wave travels a path of length `L_2` through a medium of refractive index `n_2` . After this the phase difference between the two waves is :

Options

A. `(2 pi)/(lambda) (L_(1) - L_(2))`
B. `(2 pi)/(lambda) (mu_(1) L_(1) - mu_(2) L_(2))`
C. `(2 pi)/(lambda) (mu_(2) L_(1) - mu_(1) L_(2))`
D. `(2 pi)/(lambda) [L_(1)/(mu_(1)) - (l_(2))/(mu_(2))]`

Answer

b

Explanation

Effective path difference is `mu_(1) L_(1) - mu_(2) L_(2)`.