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