Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Sound Intensity

  1. Apr 25, 2007 #1
    This problem for some reason is giving me serious problem:

    A 1.00 kHz tone issued from a loudspeaker has an intensity of 100. dB at a distance of 2.50 meters. If the speaker is assumed to be a point source, how far from the speaker will the sound (a) have an intensity of 60.0 dB and (b) be barely audible.

    Now I'm not asking for someone to solve this problem for me at all. I was wondering if there is anyone who would have any ideas of how to arrive at the answer. I tried using [Intensity = Power \ (4)(3.14159)(r)^2] to solve for the power, and then use the same equation once more to solve for the distance at which the intensity is 60 dB. The teacher gave me the answers to this problem and asked me to find the method, which I thought would be easy, but I was wrong I guess.
  2. jcsd
  3. Apr 25, 2007 #2


    User Avatar
    Homework Helper

    Your approach seems agreeable. Maybe if you would show us some calculations, in particular with the dB -> linear scale conversions.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook