1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Light question (interference)

  1. Jul 22, 2009 #1
    1. The problem statement, all variables and given/known data

    A piece of paper is placed at the end of an air wedge 4 cm long. Interference fringes appear when the light of wavelength 639 nm is reflected from the wedge. A dark fringe occurs at both the vertex of the wedge and at its paper end, and 56 bright fringes appear between. Calculate the thickness of the paper.

    2. Relevant equations

    delta X = L (lambda / 2t)

    where t is the thickness of the paper
    lambda = wavelength
    l = length of air wedge
    X = distance between fringes.
  2. jcsd
  3. Jul 22, 2009 #2
    nevermind i got it im stupid :(
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook