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Homework Help: Speed of Sound in Air

  1. Apr 25, 2010 #1
    1. The problem statement, all variables and given/known data

    I want to carry out an experiment in order to make accurate measurement of the speed of sound in air.

    We will measure the speed of sound waves in air by measuring the time required for a short sound pulse to travel from its source to a receiver. This time interval is short and is
    measured with the help of an instrument called an oscilloscope. The experimental setup is shown in the figure below:

    [PLAIN]http://img130.imageshack.us/img130/8742/18948898.gif [Broken]

    The sound wave from T is picked up by a receiver (R).

    The transmitter & receiver have resonant frequency somewhere between 38 kHz to 42 kHz. Once we set the the signal generator to the resonant frequency, at which amplitude the wave length [tex]\lambda[/tex] of the sound can be measured this way: first adjust the position of R so that the two waves displayed on the oscilloscope are in phase ; second shif R backward or forward until the two waves are back in phase; third since R must have travelled by [tex]\lambda[/tex] to bring the two waves back in phase, the difference between the initial and final position of R is equal to one [tex]\lambda[/tex].

    (i) Come up with a systematic method to measure the wave length [tex]\lambda[/tex].

    (ii) Find the velocity using [tex]v=\lambda f[/tex]. Then list as many systematic errors as you can.

    3. The attempt at a solution

    (i) What is it meant by a "systematic method" for measuring the wave length? Is it reffering to an accurate way of measuring it (like repeating the experiment a few times and averaging the results)?

    (ii) I think the systematic errors in this experiment are related to the systematic errors in measuring the wave length. But I don't know what those errors might be ....

    What systematic error is the most significant?
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Apr 26, 2010 #2
    Any suggestions guys?
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