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 produced by jet planes

  1. Apr 23, 2010 #1
    plz reply me
    i have a doubt. if two jet planes are flying together each producing 130 db sound. then what is the level of loudness heared by a person standing there. no other parameters are known. I have two concepts in mind ie) 1. every fundamental frequency produce hormonics and when two similar sin waves travel together they form a single sin wave. 120 db sound is threshhold of pain.i dont know whether this concept is useful or some another concept is there plz explan it.
    thanks in advance
     
  2. jcsd
  3. Apr 23, 2010 #2
    two similar sin waves travel together they form a single sin wave

    What you are talking about is interference. Due to lack of information you can't really use that in this problem.

    Decibels is the logarithmic scale of intensity. If you put two planes together (ignoring interference) the intensity at any point will double. How will that affect the decibel reading?

    Hint: The dB reading doesn't double.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook