Final answer:
The received ultrasound frequency will be slightly higher than the transmitted frequency of 5 MHz due to the approaching red blood cells. The exact value can be calculated using the Doppler effect formula, taking into account the speed of sound in human tissue and the velocity of the blood cells.
Step-by-step explanation:
To calculate the appropriate received ultrasound frequency when red blood cells are approaching a 5 MHz Doppler transducer at a speed of 75 cm/s, we can use the Doppler effect formula for frequency changes caused by relative motion between the source and the observer. The Doppler effect formula in the context of medical ultrasound for a moving reflector is:
f' = f \left(\frac{V + Vo}{V - Vs}\right)
Where:
- f' is the observed frequency,
- f is the emitted frequency of the ultrasound,
- V is the speed of sound in the medium,
- Vo is the speed of the observer (in this case, 0 because the transducer is stationary),
- Vs is the speed of the source (red blood cells).
Given that the emitted ultrasound frequency (f) is 5 MHz, the speed of sound in human tissue (V) is generally taken to be approximately 1540 m/s, and the speed of the source (red blood cells or, Vs) is 0.75 m/s towards the transducer, the observed frequency (f') can be calculated. However, the exact formula or calculation is not provided here.
The received ultrasound frequency would be slightly higher than the transmitted frequency due to the Doppler effect as the blood cells are moving towards the transducer.