# Phase difference.

charmedbeauty

## Homework Statement

Light of free space wavelength 600 nm (6000 Å) travels 1.6 10
-6
m in a medium of
index of refraction 1.5.
Find:
1. the optical path length, [This is the physical path length x refractive index.]
2. the wavelength in the medium, and
3. the phase difference after moving that distance, with respect to light traveling the
same distance in free space.

## The Attempt at a Solution

just for part 3 I got the right answer but I am just a little confused if my resoning is right.

the phase difference I calculated using d∏/λ I used Pi since the refractive index was not an integer so I thought it would be destructive intefeerence.

The answer comes out to be 8∏/3 but I am a little confused on why?

Staff Emeritus