Chapter 1 Questions

which of the following is defined as the number of ultrasound pulses emitted in 1 seconds? a. pulse repetition period b. duty factor c. pulse repetition frequency d. spatial pulse length

PRF

Pressue is typically expressed in: A. Frequency B. Pascals C. Decibels D. Kilograms per centimeter cubed

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

Pascals or pounds per square inch

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

Pulse repetition period

The portion of the sound be more the molecules are pulled apart describes an area of? a. compression b. rarefaction c. refraction d.amplitude

Rarefaction

Which of the following describes the amount of refraction that occurs at an interface? A. Bernoulli's Law B. Poiseuille's Laws C. Law of Reflection D. Snell's Law

Snell's Law

Which of the following is described as the ability of an object to resist compression and relates to the hardness of medium? A. Stiffness B. Density C. Pressure D. Inertia

Stiffness

All of the following are true of stiffness except A. It is defines 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 reffered to as elasticity

Stiffness and propagation speed are indirectly associated

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 0.8mm

0.1 and 0.8mm

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

1 MHz

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

1 to 20 MHz

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

100%

what is the total amount of attenuation that occurs if a 6 MHz sound beam travels through 4cm of soft tissue? a. 24 dB b. 12 dB c. 6 dB d. none of the above

12 dB

Which of the following is considered the speed of sound in soft tissue? a. 660m/s b. 330m/s c. 1480m/s d. 1540m/s

1540m/s

Which of the following is described as the distance over which one cycle occurs? A. Pulse Duration B. Duty Factor C. Period D. Wavelength

Wavelength

the major component of attenuation is a. scatter b. aborption c. transmission d. refraction

absorption

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

all of the above

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

as amplitude increases, power remains the same

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

density

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

frequency

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

hundredths

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

increases

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

increases

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

intensity is halved

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

inversely related

What is the change in power if the amplitude triples? a. It doubles c. it triples b. it quadruples d. it increases nine times

it increased 9 times

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

it is equal to the period divided by the frequency

Density is typically measured in A. kilograms per centimeter cubed B. Milimeters C. Watts per centimeter squared D. Pascals

kilograms per centimeter cubed

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

lead zirconate titanate

which of the following is an appropriate unit of measurement for prop speed? a. millimeters per microsecond b. watts per centimeter squared c. microseconds d. kilohertz

millimeters per microsecond

If only the density of the 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

propagation speed will decrease

which of the following is defined as only the active time? a. duty factor b. pulse repetiton frequency c. period d. pulse durations

pulse duration

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

reduces the spatial pulse length

the change of direction of the original sound wave that occurs when sound interacts with two different tissue types that have a different prop speed is reffered to as a. wavelength b. scattering c. refraction d. absorption

refraction

The maximum value or minimum value of an acoustic variable minus the equilibrium value of that variable describes the a. Power b. density c. duty factor d. amplitude

Amplitude

An increase in pulse repition frequency would lead to what? 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

An increase in duty factor

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

Axial resolution

Which of the following would have the highest propagation speed? A. Air B. Bone C. Soft Tissue D. Water

Bone

all of the following related to the strength of the sound wave except: a. amplitude b. wavelength c. intesnity d. power

wavelength

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

wavelength

Areas of high pressure and density are referred to as A. Compressions B. Rarefactions C. Condensations D. Rarefractions

Compressions

As imaging depth increase, the pulse repition frequecy must: A. Not change B. Increase C. Decrease D. Pulse repitition frequency does not relate to imaging depth

Decrease

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

Duty Factor

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

Intensity

Which of the following would have the lowest propagation speed? A. Water B. Soft Tissue C. Bone D. Lung Tissue

Lung Tissue (660)

Micro denotes A. Millionth B. Hundredth C. Million D. Billionth

Millionth

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

Multiplying the number of cycles times the wavelength

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

One half of the operating frequency