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Homework Help: Sound intensity and distance

  1. Dec 11, 2013 #1
    1. The problem statement, all variables and given/known data

    An alarm clock makes a sound that has intensity 60 dB at a distance
    of 1 m. What is the sound intensity of 100 such clocks which are all
    100m away?
    (A) 0.6 dB (B) 40 dB (C) 50 dB (D) 60 dB

    2. Relevant equations

    I1/I2 = R2^2/R1^2

    3. The attempt at a solution

    If it works to make a ratio...

    60 dB = 10^-6 W/m^2

    10^-6/X = 100^2/1^2

    How do the 100 clocks factor into this equation?

    Thank you!
  2. jcsd
  3. Dec 11, 2013 #2


    Staff: Mentor

    I think the 100 clocks just increases the intensity by 100x.
    Last edited: Dec 11, 2013
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