1. Not finding help here? Sign up for a free 30min 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!

Waves (antiphase)

  1. Dec 14, 2016 #1
    1. The problem statement, all variables and given/known data
    capture1-jpg.110378.jpg

    2. Relevant equations


    3. The attempt at a solution
    For the first part I know the wavelength of light is (1.53 x 414nm) = 633nm

    But for the second part I'm stumped. Since it's 180 degrees then the waves are in antiphase but I don't understand how to calculate the vertical distance?? (If antiphase then the path difference is (n+0.5)(lambda) )
     

    Attached Files:

  2. jcsd
  3. Dec 14, 2016 #2

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Waves going to A and getting reflected there to get back to the emitter take a longer path than waves getting reflected at B. How much longer?
    That formula is useful.
     
  4. Dec 17, 2016 #3
    I've taken another look but I'm still confused. Can you help out?

    Since it's 180 degrees out of phase then that means it's half a wavelength behind so n would be 0.5, right?
     
  5. Dec 17, 2016 #4

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    n is always an integer. the "0.5" are added to n already.

    Person X and Y both start at the same place. Person X goes to point B and back to the start. Person Y goes to point A, which is a distance d behind point B, and then goes back to the start. What is the difference in the path lengths of person X and Y?

    The difference from above is equal to (n+0.5)(lambda) for some integern n. Which integer n leads to the smallest distance d?
     
  6. Dec 18, 2016 #5
    Dude, that's the answer.
     
  7. Dec 18, 2016 #6
    P.s. Don't forget that the light reflected from A covers the distance between A and B twice.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Waves (antiphase)
  1. Wave ? (Replies: 3)

  2. Waves (Replies: 2)

  3. : waves (Replies: 5)

  4. Spherical waves (Replies: 1)

Loading...