A Doppler blood flow unit emits ultrasound at 5.0 MHz.
What is the frequency shift of the ultrasound reflected from blood moving in an artery at a speed of 0.20 m/s?
Express your answer using two significant figures.
f' = f0(v/v-Vs)
frequency shift = f' - f0
f0 = 5*10^6 Hz
v = 1500 m/s (assumed)
Vs = 0.20 m/s
The Attempt at a Solution
Plugging in the numbers we get the following equation for frequency shift:
Which comes out to approx 666 Hz. or 6.7 *10^2 Hz using 2 significant figures. However, this problem comes from an online hw set and according to that 6.7 *10^2 is not the correct solution.
Does anyone have an idea of what I am doing wrong? Thanks in advance for any and all help!