Destructive interference
A mixture of red light (vacuum = 661 nm) and green light (vacuum = 551 nm) shines perpendicularly on a soap film (n = 1.41) that has air on either side. What is the minimum nonzero thickness of the film, so that destructive interference causes it to look red in reflected light?
answer in nanometers
https://brainmass.com/physics/phase-changes/destructive-interference-17874
Solution Preview
n= 1.41
lambda red= 661 nm
lambda green= 551 nm
For maximum intensity, 2dn=(m+1/2)lambda --- Eq (1)
For minimum intensity, 2dn=(m)lambda --- Eq (2)
The term 1/2 is introduced to take into account the phase change on ...
Solution Summary
The solution calculates thickness of a soap film using the concept of destructive interference
$2.19