# 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
Can you calculate the path length through that medium? (express your answer in wavelengths)

charmedbeauty
Can you calculate the path length through that medium? (express your answer in wavelengths)

path length= actual length × (refractive index)

→ pathlength/wavelength.

= λ wavelengths

??