The calibration for a piece of ultrasound equipment states that the velocity of blood flow in the aorta is normally about 0.28 m/s, and the detector emits at a frequency of 4.20 MHz. If the cross sectional area of the aorta is partially blocked by plaque build-up on the walls, such that it is 1/2 its normal cross sectional area, what are the frequency and beat frequency received at the detector? (All other factors, apart from the decrease in cross sectional area, are considered to be constant.)
Also, if the ultrasound waves were directed along the blook flow and reflected from the red blood cells, what frequency would be received back at the detector? (Assume that the waves travel with a speed of 1.5 E3 m/s, which is close to that of the sound of water.) I got the answer to be 0.187 MHz, is this correct?
Also, what is the beat frequency for this situation? (The signal you receive is the beat frequency, the difference between the sent and received signals. This is what you use for comparisons.) I got the answer to be 4.013 MHz. Is this correct?
Thank you so much for any help! =D
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