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Homework Help: Sound Wave

  1. Jan 22, 2015 #1
    1. The problem statement, all variables and given/known data
    A small source emits sound waves with a power output 80W.
    a) find the intensity at a point 3.0m from the source. (0.71W/m)
    b) find the intensity level at the same point as part a.(118.51)
    c) at what distance would the intensity be one-fourth as much as of that part (a).

    i have no problem finding the answer for a and b, but i did have a bit of problem in c. i have tried to answer it which i get r=7.173, but i dont know is it right or wrong. help me for C.

    2. Relevant equationsc

    Ia=P/4pie r^2

    3. The attempt at a solution
    I=p/4pie R^2

    i get 7.173 after calculate it.
  2. jcsd
  3. Jan 22, 2015 #2


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    Education Advisor
    Gold Member

    Check your arithmetic. How much is pi? How much is R? How much is 4 pi R^2?
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