Post a New Question

Physics please explain

posted by .

Can you please explain your answer. How did you get blue lamda. Is it because red and green makes blue? How do I find the value of blue lambda?


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?
nm



For Further Reading


Physic please help! - bobpursley, Wednesday, November 14, 2007 at 7:30am
Wouldnt the thickness be blue lamda/4? ?

  • Physics please explain -

    Bob may have meant to say green light, not blue. The wavelength requirement for minimum reflection is given at
    http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/soapfilm.html
    For normal incidence and first order destructive interference of reflected green light,
    2 N d = lambda(green)
    N is the index of refraction.

  • Physics please explain -

    I meant green. Sorry.

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question