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An echocardiogram uses 4.4 MHz ultrasound to measure blood flow in the aorta. The blood is moving away from the probe at 1.4 m/s. What is the frequency shift of the reflected ultrasound?

User Rnxfod
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1 Answer

3 votes

Answer:


\Delta f=17959.2\ Hz

Step-by-step explanation:

Given:

  • original frequency of the wave,
    f=4.4* 10^6\ Hz
  • velocity of the blood stream moving away,
    v=1.4\ m.s^(-1)

Doppler shift is given as:


(f)/(f_o) =(s+v_s)/(s-v_o)

where:

s = velocity of ultrasound in blood =
1570\ m.s^(-1)


v_s= velocity of sound source towards the observer


v_o= velocity of the observer away from the source


(4.4* 10^6)/(f_o) =(1570+0)/(1570-1.4)


f_o=4396076.43\ Hz

Therefore the shift in frequency:


\Delta f=f-f_o


\Delta f=3923.56\ Hz

User Xclusive
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