Answer:
= 3.7 radians = effective phase difference
Explanation:
Wavelength given =
n1 = 1.2 and n2 = 1.5
The light rays are traveling at different speeds inside the 2 different layers.
So effective optical path is given by n d
where n is the refractive index of the medium and
d is the length traveled by the light ray in the medium.
The path difference introduced because of 2 different medium is
length = distance traveled by the wave = d = 2.5 x 10^-6 m
Phase difference = * path difference
path difference = (n₂ - n₁ ) d
= (1.5 - 1.2) (2.5 x 10⁻⁶)
= 7.5 x 10⁻⁷ m
phase difference = 2 pi / (470 x 10⁻⁹) * (7.5 x 10⁻⁷) = 10 rad
2 pi radians is 360 degrees
10 radians = 573 degrees
Phase difference = 573 - 360 = 212 degrees
= 3.7 radians = effective phase difference