Physical Principles Penny

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

0.1-0.8mm

Which of the following would be considered ultrasonic? a. 10 Hz b. 18 kHz c. 0.5 MHz d. 200 Hz

0.5 MHz

The typical range of frequency for diagnostic ultrasound imaging is a. 20-20,000 Hz b. 1-20 MHz c. 2-15 kHz d. 12-100 MHz

1-20 MHz

The DF for CW ultrasound is a. 1.0% b. 100% c. 20,000 Pa d. 8 Pa

100%

What is the total amount of attenuation that occurs is a 6.0 MHz sound beam travels through 4cm of soft tissue? a. 24 dB b. 12 dB c. 6 dB d. 1.5 dB

12 dB

Which of the following would be considered the speed of sound in soft tissue? a. 1.54 m/s b. 0.77 m/s c. 100 mW/cm^2 d. 1540 m/s

1540 m/s

If the angle of incidence is 40, what is the angle of transmission at the interface if medium 1 has a prop speed of 1320m/s and medium 2 has a prop speed of 1700m/s? a. 0 b. >40 c. <40 d. cannot tell

>40

The % of time that ultrasound system is producing pluses of ultrasound describes the a. PRP b. PD c. DF d. PRF

DF

What is defined as only the active time? a. DF b. PRF c. Period d. PD

PD

What is defined as the number of ultrasound pulses emitted in 1 second? a. PRP b. DF c. PRF d. SPL

PRF

What time is defined as the beginning of on pulse to the beginning of the next pulse and, therefore, includes both the "on" and "off" time? a. PRP b. PD c. DF d. PRF

PRP

What are units for pressure?

Pascals (Pa)

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

Snell's law

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

absorption

The max value or min value of an acoustic variable minus the equilibrium value of that variable describes: a. Power b. Intensity c. Duty Factor d. Amplitude

amplitude

An increase in PRF would lead to a. an increase in DF b. a decrease in PD c. an increase in the number of cycles d. a decrease in resolution

an increase in DF

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 increase, power remains the same

As a sound wave travels through the human body, the intensity of the sound wave decreases as a result of: a. attenuation b. elevational res c. Huygen's principle d. refraction

attenuation

Adding damping to the transducer improves which type resolution? a. trv res b. temporal res c. axial res d. elevational res

axial

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

bone

Areas of high pressure and density are referred to as a. compressions b. rarefactions c. diffractions d. refractions

compressions

As imaging depth increases, the PRF must a. not change b. increase c. decrease d. PRF does not relate to imaging depth

decrease

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

density

What is determined by sound source only? a. frequency b. wavelength c. SPL d. prop speed

frequency

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

halved

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

hundredths

As imaging depth increases, PRP a. remains constant b. increases c. decreases d. doubles

increases

What term is defined as "the power of a wave divided by the area over which the power is distributed?" a. amplitude b. power c. intensity d. aborption

intensity

Density and prop speed are ______ related.

inversely

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

it increases nine times

All of the following are true of wavelength except: a. it is determined by both the medium and 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. Millimeters 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. tungsten acetate b. dilithium zirconium c. lead zirconate titanate d. Barium sulfate

lead zirocnate titanate

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

lung tissue

Sound is technically a : a. transverse and longitudinal wave b. Mechanical and transverse wave c. non mechanical and pressure wave d. mechanical and longitudinal wave

mechanical longitudinal wave

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

millionth

What is an appropriate unit of measurement for prop speed? a. mm/us b. W/cm^2 c. ms d. kHz

mm/us

SPL can be calculated by a. multiplying the number of cycles by the frequency b. dividing the period by the frequency c. multiplying the number of cycles by the wavelength d. dividing the number of cycles by the wavelength

multiplying the number of cycles by 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

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

pascals

If only the density of a medium is increased, then the: a. prop speed will increase b. prop speed will decrease c. prop speed will stay the same d. none of the above

prop speed will decrease

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

rarefaction

Damping of the sound beam a. reduces the SPL b. increases the SPL c. increased the PD d. has no impact on SPL or PD

reduces the SPL

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

refraction

Which of the following requires an oblique interface and a prop speed mismatch? a. reflection b. refraction c. normal incidence d. damping

refraction

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

stiffness

What are the units of DF? a. dB b. dB/cm c. Hz d. unitless

unitless

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

wavelength

What is determined by both sound source and medium? a. prop speed b. frequency c. period d. wavelength

wavelength

Which of the following is described as the distance over which on cycle occurs? a. PD b. DF c. Period d. wavelength

wavelength