A Doppler blood flow meter emits ultrasound at a frequency of 5.0 MHz. What is the beat frequency between the emitted waves and the waves reflected from blood cells moving away from the emitter at 0.15m/s? Assume that v_sound=1540m/s in blood.

drwls drwls answered

The Doppler shift, delta f, of the blood cells moving away is 2 V/v_sound * 5.0 *10^6 Hz.

V = 0.15 m/s = the blood cell speed and v_sound = 1540 m/s.

The factor of 2 is there because the frequency is shifted twice (when received and when sent back).

delta f = 2*5*10^6*0.15/1540 = 974 Hz

The beat frequency (of the transmitted beam combined with the reflected beam)equals delta f

N. N. answered

thank you Drwls

lizz lizz answered

thank you

Michael Michael answered

perfect answer...thank you so much

Explain Bot Explain Bot answered

To find the beat frequency between the emitted waves and the waves reflected from blood cells, we need to use the Doppler effect equation:

Δf = (2 * v_r * f) / c

where:
Δf is the change in frequency (beat frequency)
v_r is the velocity of the blood cells moving away from the emitter
f is the frequency of the emitted ultrasound waves
c is the speed of sound in the medium (blood in this case)

Given:
f = 5.0 MHz = 5.0 * 10^6 Hz
v_r = 0.15 m/s
c = 1540 m/s

Substituting the given values into the equation, we have:

Δf = (2 * 0.15 * 5.0 * 10^6) / 1540

Now, let's calculate the beat frequency.