1. Not finding help here? Sign up for a free 30min 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!

Power from sound

  1. Aug 16, 2015 #1
    1. The problem statement, all variables and given/known data
    Fans at a stadium produce sound that is heard 1km away, the intensity level is 60 dB. How much acoustic power is generated by the fans?

    2. Relevant equations
    B = 10 log (I÷I_0)
    P=I*A

    3. The attempt at a solution
    I= 10^-12*6^10= 10^-6W/m^2
    P= 10^-6*4pi*1000^2 =12.56W

    However the right answer should be 6.28W
     
  2. jcsd
  3. Aug 16, 2015 #2

    NascentOxygen

    User Avatar

    Staff: Mentor

    Hi triforce. :welcome:

    Do you need to consider: would sound be absorbed, or reflected, by the stadium floor?

    There's a typo in your working, too.
     
  4. Aug 16, 2015 #3
    As the sound is radiated into a hemisphere rather than a sphere, the surface area is halved.
     
  5. Aug 16, 2015 #4
    Ah! That makes sense!

    Thank you very much!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Power from sound
Loading...