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: Phase Difference

  1. Oct 19, 2011 #1
    1. The problem statement, all variables and given/known data
    Sources A and B emit long-range radio waves of wavelength 550 m, with the phase of the emission from A ahead of that from source B by 90°. The distance rA from A to a detector is greater than the corresponding distance rB from B by 140 m. What is the magnitude of the phase difference at the detector?

    2. Relevant equations

    3. The attempt at a solution

    Initially, source A leads source B by 90°, which is equivalent to \frac{1}{4} wavelength.
    However, source A also lags behind source B since rA is longer than rB by 140 m, which is \frac{140}{550}=0.2545 wavelength. So the net phase difference between A and B at the
    detector is -0.732 Rad.

    This is wrong though, can someone help me =D
    Last edited: Oct 19, 2011
  2. jcsd
  3. Oct 19, 2011 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Education Advisor

    How'd you come up with -0.732 rad? It looks like you completely ignored one of the terms.
  4. Oct 19, 2011 #3
    To be honest I'm not sure.
    I have tried everything I can think off but all my answers are wrong.
  5. Oct 19, 2011 #4
    Thank you for your time but I asked a friend and he showed me. It was just a stupid mistake that I missed thank yiu
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook