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!

How to calculate slit separation?

  1. Feb 23, 2016 #1
    1. The problem statement, all variables and given/known data
    Light of wavelength 680 nm falls on two slits and produces an interference pattern in which the fourth order fringe is 38 mm from the central fringe on a screen 2.0 m away. What is the separation of the two slits?

    2. Relevant equations
    d * sin(theta) = m * lambda

    3. The attempt at a solution
    I tried to calculate the slit separation using the equation above but I'm not sure about the angle. Using tan^-1(.038/2), I got an angle of 1.1 degrees which then led me to a d value of 1.41 x 10^-4 m, but the answer given by the book is .085 mm so I'm just completely lost at this point.
     
  2. jcsd
  3. Feb 23, 2016 #2

    blue_leaf77

    User Avatar
    Science Advisor
    Homework Helper

    I also get a similar answer as yours.
     
  4. Feb 23, 2016 #3
    Perhaps the book is wrong or something then.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted