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Homework Help: Ear Damage from a Small Firecracker

  1. Oct 5, 2005 #1
    Lets say there is a small firecracker that emits 1200 of peak power.
    What is the peak intensity B in decibels at a distance of 1 m from the firecracker?

    This is what i have tried:

    B = 10log(I/Io)

    I = 1200/pi Since I = power/area and the area is pir^2, pi(1m)^2

    Io=( 10^-12 W/m^2)

    So B= 10log([1200/pi] / [10^-12 ]) and i get around 135.83 , however the answer is incorrect

    Can someone help please? THank you
  2. jcsd
  3. Oct 5, 2005 #2
    Check the way you defined area for waves that propagate in space.
  4. Oct 5, 2005 #3
    So the area is not a circle?
  5. Oct 5, 2005 #4
    No, sound waves are spherical waves and travel in three dimensional space.
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