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Homework Help: What is the beat frequence in Hz of ultrasound

  1. Apr 26, 2005 #1
    Ultrasound reflected from an oncoming bloodstream that is moving at a 30 cm/s is mixed with the original frequency of 2.5 MHz to produce beats. What is the beat frequency in Hz? (Velocity of sound in blood = 1540 m/s.)
  2. jcsd
  3. Apr 26, 2005 #2


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    Find the frequency of the reflected wave using the "doppler effect" equation. Remember that the bloodstream is moving towards the observer.

    Then use the beat equation with the two frequencies (2.5MHz and what you get above using doppler).

    Careful with your units.
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