Review: Physics Principles
1. Which of the following is described as the ability of an object to resist compression and relates to the hardness of a medium? a. Stiffness b. Density c. Pressure d. Inertia
A
10. Micro denotes: a. Millionth b. Hundredth c. Million d. Billion
A
13. Areas of high pressure and density are referred to as: a. Compression b. Rarefactions c. Condensations d. Rarefractions
A
15. Density is typically measured in: a. Kilograms per centimeter cubed b. Millimeters c. Watts per centimeter squared d. Pascals
A
2. An increase in pulse repetition frequency would lead to: a. An increase in duty factor b. An increase in pulse duration c. An increase in the number of cycles d. A decrease in resolution
A
21. Density and propagation speed are: a. Inversely related b. Directly related c. Directly proportional d. Unrelated
A
22. All of the following are true of power except: a. As amplitude increase, power remains the same b. Power is proportional to amplitude squared c. Intensity is proportional to power d. Power is measured in milliwatts
A
28. Which of the following is determined by the sound source only? a. Frequency b. Wavelength c. Spatial pulse length d. Propagation speed
A
32. Which of the following is an appropriate unit of measurement for propagation speed? a. millimeters per microsecond b. watts per centimeter squared c. microseconds d. kilohertz
A
38. Damping of the sound beam: a. Reduces the spatial pulse length b. Increases the spatial pulse length c. Increases the pulse duration d. Has no impact on spatial pulse length or pulse duration
A
40. What is defined as the beginning of one pulse to the beginning of the next pulse, and therefore includes both the "on" and "off" time? a. Pulse repetition period b. Pulse duration c. Duty factor d. Pulse repetition frequency
A
9. The attenuation coefficient in soft tissue is equal to: a. One half the operating frequency b. Double the operating frequency c. Frequency times path length d. The total decibels
A
12. All of the following are true of stiffness except: a. It is defined as the ability of an object to resist compression b. Stiffness and propagation speed are indirectly associated c. Increasing stiffness increases propagation speed d. Stiffness may also be referred to elasticity
B
17. What is the total amount of attenuation that occurs if a 6.0-MHz sound beam travels through 4 cm of soft tissue? a. 24 dB b. 12 dB c. 6 dB d. None of the above
B
18. As imaging depth increases, pulse repetition period: a. Remains constant b. Increases c. Decreases d. Doubles
B
19. If pulse repetition frequency increases, then the duty factor: a. Remains constant b. Increases c. Decreases d. Doubles
B
23. All of the following are true of wavelength except: a. It is determined by both the medium and the sound source b. It is equal to the period divided by the frequency c. It is inversely related to frequency d. It is directly related to period
B
29. The prefix "centi" means a. Thousandths b. Hundredths c. Millions d. Hundreds
B
3. Which of the following would have the highest propagation speed? a. Air b. Bone c. Soft tissue d. Water
B
30. If the angle of incidence is 40°, what is the angle of transmission at the interface if medium 1 has a propagation speed of 1320 m/s and medium 2 has a propagation speed of 1700 m/s? a. <40° b. >40° c. 40° d. Cannot tell the angle of transmission
B
33. The major component of attenuation is: a. Scatter b. Absorption c. Transmission d. Refraction
B
35. The duty factor for continuous wave ultrasound is: a. <99% b. 100% c. >20,000 Hz d. 8 Pa
B
36. All of the following relate to the strength of the sound wave except: a. Amplitude b. Wavelength c. Intensity d. Power
B
37. What is the change in intensity if the power decreases by half? a. Intensity doubles b. Intensity is halved c. Intensity is one fourth d. Intensity does not change
B
41. What is pressure measured in? a. feet, inches, centimeters, or miles b. pascals or pounds per square inch c. kilograms per centimeter cubed d. hertz, kilohertz, or megahertz
B
45. The portion of the sound beam where the molecules are pulled apart describes an area of: a. Compression b. Rarefraction c. Refraction d. Amplitude
B
46. If only the density of a medium is increased, then the: a. Propagation speed will increase b. Propagation speed will decrease c. Propagation speed will stay the same d. None of the above
B
7. Pressure is typically expressed in: a. Frequency b. Pascals c. Decibels d. Kilograms per centimeter cubed
B
8. The typical range of frequency for diagnostic ultrasound imaging is: a. 20 to 20,000 Hz b. 1 to 20 MHz c. 10 to 20 MHz d. 12 to 100 MHz
B
14. Spatial pulse length can be calculated by: a. Multiplying the number of cycles times the frequency b. Dividing the period by the frequency c. Multiplying the number of cycles times the wavelength d. Dividing the number of cycles by the wavelength
C
20. The percentage of time that the ultrasound system is producing pulses of ultrasound describes the: a. Pulse repetition period b. Pulse duration c. Duty factor d. Pulse repetition frequency
C
25. Which of the following is defined as the number of ultrasound pulses emitted in 1 second? a. Pulse repetition period b. Duty factor c. Pulse repetition frequency d. Spatial pulse length
C
27. The inertia of the medium describes the: a. Attenuation characteristics b. Stiffness c. Density d. Elasticity
C
31. The change in the direction of the original sound wave that occurs when sound interacts with two different tissue types that have a different propagation speed is referred to as: a. Wavelength b. Scattering c. Refraction d. Absorption
C
39. What is defined as the ability of the ultrasound system to image structures that are positioned parallel to the sound beam as separate structures? a. Transverse resolution b. Parallel resolution c. Axial resolution d. Coronal resolution
C
42. What is essentially equal to the power of a wave divided by the area over which the power is distributed? a. Amplitude b. Power c. Intensity d. Absorption
C
43. Transducers have material within them that, when electronically stimulated, produce ultrasound waves. This is most likely some form of: a. Copperhirm titonize b. Zinconian sulfate c. Lead zirconate titanate d. Barium
C
49. Which of the following would be considered ultrasonic? a. 10 Hz b. 12.5 Hz c. 1 MHz d. 200 Hz
C
5.As imaging depth increases, the pulse repetition frequency must: a.Not change b.Increase c.Decrease d.Pulse repetition frequency does not relate to imaging depth
C
11. Which of the following is described as the distance over which one cycle occurs? a. Pulse duration b. Duty factor c. Period d. Wavelength
D
16. As a sound wave travels through the human body, the intensity of the sound wave decreases as a result of: a. Attenuation b. Absorption c. Scattering d. All of the above
D
24. Which of the following is determined by the sound source and medium? a. Propagation speed b. Frequency c. Period d. Wavelength
D
26. Which of the following is defined as only the active time? a. Duty factor b. Pulse repetition frequency c. Period d. Pulse duration
D
34. In clinical imaging, the wavelength measures between: a. 1 and 10 Hz b. 1540 and 2000 m/s c. 0 and 1 d. 0.1 and 0.8 mm
D
4.Which of the following would have the lowest propagation speed? a.Water b.Soft tissue c.Bone d.Lung tissue
D
44. What is the change in power if the amplitude triples? a. It doubles b. It triples c. It quadruples d. It increases nine times
D
47. Sound is technically a: a. Transverse and longitudinal wave b. Mechanical and transverse wave c. Nonmechanical and pressure wave d. Mechanical and longitudinal wave
D
48. The maximum value or minimum value of an acoustic variable minus the equilibrium value of that variable describes the: a. Power b. Intensity c. Duty factor d. Amplitude
D
50. Which of the following is considered the speed of sound in soft tissue? a. 660 m/s b. 330 m/s c. 1480 m/s d. 1540 m/s
D
6. Which of the following describes the amount of refraction that occurs at an interface? a. Bernoulli's law b. Poiseuille's law c. Law of reflection d. Snell's law
D
