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: Determine radius of wavelength

  1. Jan 22, 2014 #1
    1. The problem statement, all variables and given/known data

    In the figure, sound with a 38.0 cm wavelength travels rightward from a source and through a tube that consists of a straight portion and a semicircle. Part of the sound wave travels through the semicircle and then rejoins the wave that goes directly through the straight portion. This rejoining results in interference. What is the smallest radius r that produces an intensity minimum at the detector?

    Also a picture: http://gyazo.com/68576b343c662325703528445328da23


    d (cm)
    r (cm) - needed

    2. Relevant equations

    None (that I know of)

    3. The attempt at a solution

    I honestly have no idea how to solve this, I feel like it is very simple and I am over thinking it. I cannot find any relevant equations, because I feel like I don't have enough information to even need an equation.

    Can anyone point me in a better direction here please?
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jan 22, 2014 #2


    User Avatar
    Homework Helper

    an intensity minimum means that one path is ½ wavelength longer than the other path, so the 2 waves cancel.
  4. Jan 22, 2014 #3
    Nvm, figured it out.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted