Physics Doppler UPDATED ACTUAL Exam Questions and CORRECT Answers

Physics Doppler UPDATED ACTUAL
Exam Questions and CORRECT Answers

Doppler Shift AKA - CORRECT ANSWER- ✔✔Doppler Frequency



The Doppler Effect - CORRECT ANSWER- ✔✔An apparent change in frequency as a result
of a change in wavelength caused by motion of a wave source relative to an observer


Relative motion between the sound source & the receiver creates - CORRECT ANSWER-
✔✔a frequency change


The frequency of sound changes when the sound source & the receiver - CORRECT
ANSWER- ✔✔move closer together or father apart



Amount of increase or decrease (in frequency) depends on: - CORRECT ANSWER- ✔✔-
Speed of motion
- Angle between the wave propagation direction
- Motion direction
- Frequency of wave emitted by the source


The frequency does not change when the distance between the sound source & the receiver -
CORRECT ANSWER- ✔✔remains constant



The Doppler Principle - CORRECT ANSWER- ✔✔is used to measure red blood cell
velocities


As the velocity increases, the Doppler shift - CORRECT ANSWER- ✔✔increases


If the detected frequency is *lower* than the transmitted frequency, the Doppler shift is -
CORRECT ANSWER- ✔✔negative

,If the detected frequency is *higher* than the transmitted frequency, the Doppler shift is -
CORRECT ANSWER- ✔✔positive



The Doppler shift is - CORRECT ANSWER- ✔✔a low frequency that "rides" on top of the
much higher transducer frequency


Demodulation - CORRECT ANSWER- ✔✔a process that extracts the low Doppler frequency
from the transducer's carrier frequency


Transducer frequencies of __________________ are used to perform Doppler exams -
CORRECT ANSWER- ✔✔2 MHz - 10 MHz


Doppler shifts range from _______________________ & fall into the audible range of sound
- CORRECT ANSWER- ✔✔20 Hz - 20,000 Hz (20 KHz)



Doppler Shift = - CORRECT ANSWER- ✔✔Reflected Frequency - Transmitted Frequency



Doppler shifts are created when - CORRECT ANSWER- ✔✔transmitted waves strike
moving RBCs


(+) Doppler shift occurs when blood moves _____________ the transducer - *the reflected
frequency is higher than the transmitted frequency* - CORRECT ANSWER- ✔✔towards


(-) Doppler shift occurs when blood moves __________ from the transducer - *the reflected
frequency is lower than the transmitted frequency* - CORRECT ANSWER- ✔✔away



X-axis of the Doppler spectrum represents - CORRECT ANSWER- ✔✔time



Y-axis represents the - CORRECT ANSWER- ✔✔Doppler shift or velocity


Doppler frequencies indicate _____________, not speed - CORRECT ANSWER-
✔✔velocity

, Speed - CORRECT ANSWER- ✔✔a *magnitude* & indicates the distance a RBC moves in
1 sec


Speed is reported in units of - CORRECT ANSWER- ✔✔cm/sec - any unit of distance/time



Velocity - CORRECT ANSWER- ✔✔a *magnitude* & a direction


An automobile is traveling from New York to Florida at a rate of 50 miles per hour -
CORRECT ANSWER- ✔✔- Speed = 50 miles/hour (speed is a magnitude)
- Velocity is 50 miles/hour to the south (velocity is a magnitude & a direction)


Doppler Equation - CORRECT ANSWER- ✔✔Doppler Shift = 2 x velocity of blood x
transducer frequency x cos0 / propagation speed


Doppler shift is caused by - CORRECT ANSWER- ✔✔a change of wavelength caused by
motion relative to the observer


Wavelength = - CORRECT ANSWER- ✔✔Propagation Speed / Frequency



When frequency increases, wavelength - CORRECT ANSWER- ✔✔decreases



When wavelength decreases, Doppler shift - CORRECT ANSWER- ✔✔increases



When Doppler shift increases, Transmit Frequency - CORRECT ANSWER- ✔✔increases


Propagation velocity & wavelength are ____________ related - CORRECT ANSWER-
✔✔directly


Doppler shift is ___________ related to the frequency of transmitted sound - CORRECT
ANSWER- ✔✔directly