Physic please help!
posted by Mary .
A mixture of red light (vacuum = 661 nm) and green light (vacuum = 551 nm) shines perpendicularly on a soap film (n = 1.35) 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?
Wouldnt the thickness be blue lamda/4? ?