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Homework Help: Ultrasound transmitter component- longitudinal or transverse waves?

  1. Feb 14, 2008 #1
    Pretty basic question, i think, it's either possible or it's not.

    Physics practical using an ultrasound generator and receiver components (in separate circuits, with the the generator rigged up to signal generator, and the receiver connected to an oscilloscope to take readings from). For the write up i need some background theory about ultrasound and the sensors and basically i wondered are the waves being transmitted longitudinal or transverse? Will it be specific to the type of ultrasound sensor i have? If not is there something in the specification for the sensors (which is brief) from which i would be able to tell?

    Thankyou very much :)
    Last edited: Feb 14, 2008
  2. jcsd
  3. Feb 14, 2008 #2


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    I think you are confusing them with radio transmitters.
    Ultrasound is just pressure pulses in the air (or other medium)
  4. Feb 14, 2008 #3
    Sounds waves will always be longitudinal waves
  5. Feb 14, 2008 #4
    thanks for the quick reply! sorry, dim moment i think, i swear i did look elsewhere first D:
  6. Feb 14, 2008 #5
    ok, another additional one here, is the transmitter sending pulses of ultrasound or is it continuous? The spec doesn't say. On the oscilloscope it appeared as a continuous wave but i don't really know how to use one and my teacher showed me specifically for the experiment, so that may not be here or there!

    (thankyou again)
    Last edited: Feb 14, 2008
  7. Feb 14, 2008 #6
  8. Feb 24, 2009 #7
    if the ultrasound signal is propagating (transmitting) through the air or water then the wave mode is longitudinal,(shear/traverse waves don't propagate in liquids or gases) but if it is propagating through a solid it depends on how the ultrasound transmitter is exciting the solid. For example if the transmitter is propagating straight into the solid ( that is perpendicular to the surface of the solid) a longitudinal wave will propagate through the material but if the transmitter is angled (e.g 45 degrees) to the surface a traverse wave maybe produced.
  9. Feb 24, 2009 #8
    pulsed or contiuous wave. Probably pulsed, but if it looks like a typical sine wave a sine wave is being produced, you will have to check with vendor of manufacturer for spec sheet to be sure, but the single that appears on the oscilloscope should be the signal that is being produced, if your experiemnt is setup correctly and you are not getting a signal from somewhere else. check the frequency of the signal on the scope, is it the same as the spec of the ultrasound transmitter states?
  10. Feb 24, 2009 #9
    What are you trying to measure?
  11. Feb 24, 2009 #10
    That message was in relation to the question form coffee&TV about whether a lonitundinal wave or a traverse wave is produced by a ultrasound transmitter.

    But i have a question you might have seen, how does one differentiate between P waves and S waves. I want to measure the time delay between them as they arrive at a sensor for location reasons
  12. Jun 14, 2009 #11
    NO! sound waves are just mechanical waves (meaning they need a medium to propagate). I measured the transverse sound wave velocity few days ago! lol
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