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Homework Help: Waves problem. Finding phases

  1. Aug 26, 2007 #1
    1. The problem statement, all variables and given/known data

    A spherical wave with a wavelength of 2.0 m is emitted from the origin. At one instant of time, the phase at 4m is (pi) . At that instant, what is the phase at 3.5m? What is the phase at 4.5m at the same instant?

    2. Relevant equations

    ∆Φ = 2π[(∆x)/λ]

    3. The attempt at a solution

    First i set 2 as ∆x and either 3.5 or 2.5 as λ which didn't work

    Thanks in advance
    Last edited: Aug 26, 2007
  2. jcsd
  3. Aug 26, 2007 #2


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    Homework Helper

    I think you should draw a sin wave ( either just by hand or in excel) and look at roughly how high it is at 4m then look just before (ie 3.5m) and just after (4.5m).
    In introductory physics - never do the maths until you have amental picture and understand what sort of answer you are expecting. (ps this doesn't work for QM!)
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