Ultrasound physics examples

50 Practice Physics Questions

1. What is the average velocity of ultrasound in soft tissue at 5.0 MHz ?
(A) 1540 meters per millisecond
(B) 1540 meters per microsecond
(C) 1540 meters per nanosecond
(D) 1540 meters per second

2. Red blood cells are an example of a
(A) rayleigh reflector
(B) non-specular reflector
(C) strong reflector
(D) mirror reflector

3. Which has a higher acoustic impedance coefficient ?
(A) solid
(B) liquid
(C) gas
(D) all the above

4. A hyperechoic region is
(A) low amplitude
(B) anechoic
(C) echo free
(D) echogenic

5. The angle of refraction is described by
(A) Snell's law
(B) Curie's principle
(C) Huygen's principle
(D) speed differences

6. What is reflection in multiple directions from a reflector that is small relative to
the wavelength
(A) multipath artifact
(B) Snell's scattering
(C) Hguyens principle
(D) Rayleigh scattering

7. Receiver demodulation can not be controlled by the sonographer
(A) True
(B) False

8. Reflection at a tissue interface depends primarily on
(A) impedance
(B) bandwidth
(C) beam profile
(D) velocity differences

9. Azimuthal resolution is also known as
(A) lateral resolution
(B) range resolution
(C) axial resolution
(D) none of the above

10. What is the Doppler shift frequency in soft tissue if the transmitted frequency is 3
MHz and the velocity of a reflector is 20 cm/s ?
(A) 195 Hz
(B) 390 Hz
(C) 780 Hz
(D) 3.07 MHz
(E) 3.14 MHz

11. Intensity of the ultrasound beam is proportional to the square root of the
acoustic pressure
(A) True
(B) False

12. Aliasing is not a problem with color flow imaging.
(A) True
(B) False

13. Density is an acoustic variable
(A) True
(B) False

14. If the PRF increases, duty factor ___________
(A) Increases
(B) decreases
C) remains the same
(D) is unrelated

15. A-Mode is mainly used to measure distance
(A) True
(B) False

16. Period is
A) the amplitude of a wave
(B) the speed of a wave
(C) the time it takes to complete a single cycle
(D) the length it takes to complete a single cycle

17. Spatial pulse length is determined by the
(A) oscillator
(B) pulser
(C) pulse oscillator
(D) all of the above

18. Transmission angle is less than the incident angle if the propagation speed of
(A) medium 2 is less than that of medium 1
(B) medium 1 is higher than that of medium 2
(C) two media are the same
(D) none of the above

19. Diffraction is the
(A) spreading out of an ultrasound beam
(B) bending of the sound beam
(C) dissipation of heat
(D) reverse refraction

20. Annular array transducers steer the beam
(A) axially
(B) electronically
(C) mechanically
(D) none of the above

21. _______ is a Rayleigh scatterer
(A) lung
(B) liver
(C) red cell
(D) diaphragm

22. A bit is the smallest part of a digital "word"
(A) True
(B) False

23. Velocity times density equals
(A) intensity
(B) duty factor
(C) quality factor
(D) impedance

24. What is the pulse duration for five cycles of 5 MHz ultrasound ?
(A) 0.5 microsecond
(B) 1.0 microsecond
(C) 0.25 microsecond
(D) 5.0 microsecond

25. Aliasing artifacts are unique to
(A) power doppler
(B) pulsed Doppler
(C) continuous wave Doppler
(D) none of the above

26. The intensity reflection coefficient depends on acoustic impedance mismatch
(A) True
(B) False

27. Velocity of sound in a medium is constant regardless of frequency.
(A) True
(B) False

28. Density is not an acoustic variable
(A) True
(B) False

29. If the PRP increases, duty factor ___________
(A) Increases
(B) decreases
(C) remains the same
(D) is unrelated

30. A high PRF is needed to image deep structures
(A) True
(B) False

31. Longitudinal waves are
(A) parallel to the axis of the wave propagation
(B) perpendicular to the axis of the wave propagation
(C) compressed perpendicular to the axis of the wave propagation
(D) none of the above

32. Wavelength has the greatest effect on
(A) lateral resolution
(B) far zone
(C) axial resolution
(D) temporal resolution

33. What is necessary to calculate distance to a reflector ?
(A) density and pulse length
(B) density and round-trip time
(C) attenuation coefficient and reflector amplitude
(D) propagation speed and round-trip time

34. Scattering is
(A) redirection of the sound beam in many directions
(B) bending of the sound beam in any direction
(C) heat conversion
(D) none of the above

35. The percentage of ultrasound reflected at an air/liquid interface is
(A) 100%
(B) high
(C) low
(D) none

36. A specular reflector has surface texture ________ the wavelength of the incident
wave
(A) less than
(B) equal to
(C) irrelevant to
(C) greater than

37. In a cathode ray tube display device the electron beam is steered by
(A) deflection plates
(B) phased arrays
(C) photon converters
(D) voltages from the scan converter

38. If it takes 50 microseconds for a pulse to return as an echo, how deep is the
reflector ?
(A) 1 cm
(B) 2 cm
(C) 3 cm
(D) 4 cm

39. Q value is determined by
(A) frequency and bandwidth
(B) pulse duration and bandwidth
(C) impedance and bandwidth
(D) none of the above

40. Shadowing artifacts are
(A) from velocity change
(B) observed distal to cystic structures
(C) caused by differences in attenuation
(D) none of the above

41. A-mode scanning represents the depth of the signal in the horizontal dimension.
(A) True
(B) False

42. Poiseuille's equation states that the volume rate of flow through a vessel is
inversely proportional to
(A) vessel radius
(B) blood density
(C) pressure gradient
(D) blood viscosity

43. Temperature is an acoustic variable
(A) True
(B) False

44. Spatial pulse length __________ if the frequency is increased
(A) Increases
(B) decreases
(C) remains the same
(D) is unrelated

45. The Reynolds number predicts aliasing
(A) True
(B) False

46. Transverse waves are
(A) parallel to the axis of the wave propagation
(B) perpendicular to the axis of the wave propagation
(C) compressed perpendicular to the axis of the wave propagation
(D) none of the above

47. Beam diameter determines
(A) temporal resolution
(B) the number of scan lines
(C) axial resolution
(D) lateral resolution

48. Mirror image artifact is sometimes seen near the
(A) aorta
(B) gall bladder
(C) stomach
(D) diaphragm

49. The binary number 1011000 equals the decimal
number
(A) 64
(B) 101
(C) 88
(D) 1342

50. Low frequency transducers have
(A) shorter wavelengths and less penetration
(B) longer wavelengths and greater penetration
(C) shorter wavelengths and greater penetration
(D) longer wavelengths and less penetration

Answer Key

1. D

2. B
3. A
4. D
5. A
6. D
7. A
8. A
9. A
10. C
11. B
12. B
13. A
14. A
15. A
16. C
17. D
18. A
19. A
20. C
21. C
22. A
23. D
24. B
25. B
26. A
27. A
28. B
29. B
30. B
31. A

32. C
33. D
34. A
35. B
36. C
37. A
38. C
39. A

40. C
41. A
42. D
43. A
44. B
45. B
46. B
47. D
48. D
49. C
50.B