Ultrasound Physics Quiz 1

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. Pulse Repetition Period

Which of the following is described as the ability of an object to resist compression and related to the hardness of a medium? a. stiffness b. density c. pressure d. inertia

A. Stiffness

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. Intensity is halved

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. Propagation speed will decrease

The portion of the sound beam where the molecules are pulled apart describes an area of: a. compression b. rarefaction c. refraction d. amplitude

B. Rarefaction

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 as elasticity

B. Stiffness and propagation speed are indirectly associated

The inertia of the medium describes its: a. attenuation characteristics b. stiffness c. density d. elasticity

C. Density

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. Duty Factor

Transducers have material within them that, when electronically stimulated, produces ultrasound waves. This is most likely some form of: a. copperhirm titonize b. zinconian sufate c. lead zirconate titanate d. barium

C. Lead zirconate titanate

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. Multiplying the number of cycles times the wavelength

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. Pulse Repetition Frequency

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 the above

D. All of the above

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. Amplitude

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. Mechanical and Longitudinal wave

Which of the following is defined as only the active time? a. duty factor b. pulse repetition frequency c. period d. pulse duration

D. Pulse Duration

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. An increase in duty factor

All of the following are true of power except: a. as amplitude increases, power remains the same b. power is proportional to amplitude squared c. intensity is proportional to power d. power is measured in milliwatts

A. As amplitude increases, power remains the same

Areas of high pressure and density are referred to as: a. compressions b. rarefactions c. condensations d. rarefractions

A. Compressions

Which of the following is determined by the sound source only? a. frequency b. wavelength c. spatial pulse length d. propagation speed

A. Frequency

Density and propagation speed are: a. inversely related b. directly related c. directly proportional d. unrelated

A. Inversely related

Density is typically measured in: a. kilograms per centimeter cubed b. millimeters c. watts per centimeter squared d. Pascals

A. Kilograms per centimeter cubed

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. Millimeters per microsecond

Micro denotes: a. millionth b. hundredth c. million d. billionth

A. Millionth

The attenuation coefficient in soft tissue is equal to: a. one half of the operating frequency b. double the operating frequency c. frequency times path length d. the total decibels

A. One half of the operating frequency

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. Reduces the spatial pulse length

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. 1 to 20 MHz

The duty factor for continuous wave ultrasound is: a. <99% b. 100% c. >20,000 Hz d. 8 Pa

B. 100%

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. 12 dB

If the angle of incidence is 40 degrees, what is the angle of transmission at the interface if medium 1 has a propagation speed of 13 20 m/s and medium 2 has a propagation speed of 1700 m/s? a. <40 degrees b. >40 degrees c. 40 degrees d. cannot tell the angle of transmission

B. >40 degrees

The major component of attenuation is: a. scatter b. absorption c. transmission d. refraction

B. Absorption

Which of the following would have the highest propagation speed? a. air b. bone c. soft tissue d. water

B. Bone

The prefix "centi" denotes: a. thousandths b. hundredths c. millions d. hundreds

B. Hundredths

As imaging depth increases, pulse repetition period: a. remains constant b. increases c. decreases d. doubles

B. Increases

If pulse repetition frequency increases, then the duty factor: a. remains constant b. increases c. decreases d. doubles

B. Increases

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. It is equal to the period divided by the frequency

Pressure is typically expressed in: a. frequency b. Pascals c. decibels d. kilograms per centimeter cubed

B. Pascals

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. Pascals or pounds per square inch

All of the following relate to the strength of the sound wave except: a. amplitude b. wavelength c. intensity d. power

B. Wavelength

Which of the following would be considered ultrasound? a. 10 Hz b. 12.5 Hz c. 1 MHz d. 200 Hz

C. 1 MHz

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. Axial Resolution

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. Decrease

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. Intensity

The change in the directions 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. Refraction

In clinical imaging, the wavelength measures between: a. 1 and 10 Hz b. 1540 and 2000 m/s c. 0 to 1 d. 0.1 to 0.8 mm

D. 0.1 to 0.8mm

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. 1540 m/s

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. It increases nine times

Which of the following would have the lowest propagation speed? a. water b. soft tissue c. bone d. lung tissue

D. Lung tissue

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. Snell's Law

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. Wavelength

Which of the following is determined by the sound source and medium? a. propagation speed b. frequency c. period d. wavelength

D. Wavelength