Question

An ultrasound machine in a hospital uses a sound source at 5.10000MHz.

- Assuming that the speed of the ultrasound in the body is same as water (1440 m/s), determine the wavelength in the body.
- If blood cells are moving towards the sound source at a speed of 0.8 m/s, at what frequency do the crests of the sound wave pass through the blood cell?
- What is the frequency of the sound waves reflected back towards the source by the blood cells?
- If the sound level intensity is 2.0 dB at a point
*d*_{1}= 6.8 cm from the source, what is the sound intensity at that point in W/m^{2}. (We can assume that 0 dB is referenced to 10^{-12}W/m^{2}). - Assume that sound is emitted from a point source, so that the
intensity decreases quadratically with distance. What is the
intensity level in dB at a point
*d*_{2}= 2.0cm from the source?

Answer #1

An ultrasound machine in a hospital uses a sound source at
19.00000MHz.
[3 marks] Assuming that the speed of the ultrasound in the body
is same as water (1440 m/s), determine the wavelength in the
body.
[6 marks] If blood cells are moving towards the sound source at
a speed of 0.8 m/s, at what frequency do the crests of the sound
wave pass through the blood cell?
[5 marks] What is the frequency of the sound waves reflected
back...

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