Quiz 1 DMS 119

Pascals

Pressure is typical expressed in:

Mechanical and longitudinal wave

Sound is technically a:

Multiplying the number of cycles times the wavelength

Spatial pulse length can be calculated by:

One half of the operating frequency

The attenuation coefficient in soft tissue is equal to:

Refraction

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:

100%

The duty factor for continuous wave ultrasound is:

Density

The inertia of the medium describes its:

Absorption

The major component of attenuation is:

Amplitude

The maximum value or minimum value of an acoustic variable minus the equilibrium value of that variable describes the:

Duty factor

The percentage of time that the ultrasound system is producing pulses of ultrasound describes the:

Rarefaction

The portion of the sound beam where the molecules are pulled apart describes and area of:

Hundredths

The prefix "centi" denotes:

1-20 MHz

The typical range of frequency for diagnostic ultrasound imaging is:

lead zirconate titanate

Transducers have materials within them that, when electronically stimulated, produces ultrasound waves. This is most likely some form of:

Axial resolution

What is defined as the ability of the ultrasound system to image structures that are positioned parallel to the sound beam as separate structures?

Pulse repetition period

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?

Intensity

What is essentially equal to the power of a wave divided by the area over which the power is distributed?

Pascals or pounds per square inch

What is pressure measured in?

Intensity is halved

What is the change in intensity if the power decreases by half?

It increases nine times

What is the change in power if the amplitude triples?

12 dB

What is the total amount of attenuation that occurs if a 6.0-MHz sound beam travels through 4 cm of soft tissue?

Snell's law

Which of the following describes the amount of refraction that occurs at an interface?

Millimeters per microsecond

Which of the following is an appropriate unit of measurement for propagation speed?

1540 m/s

Which of the following is considered the speed of sound in soft tissue?

Pulse duration

Which of the following is defined as only the active time?

pulse repetition frequency

Which of the following is defined as the number of ultrasound pulses emitted in 1 second?

Stiffness

Which of the following is described as the ability of an object to resist compression and related to the hardness of a medium?

Wavelength

Which of the following is described as the distance over which one cycle occurs?

Frequency

Which of the following is determined by the sound source only?

Wavelength

Which of the following is determined by the source source and the medium?

1 MHz

Which of the following would be considered ultrasound?

Bone

Which of the following would have the highest propagation speed?

Lung tissue

Which of the following would have the lowest propagation speed?

As amplitude increases, power remains the same

All of the following are true of power except:

Stiffness and propagation speed are indirectly associated

All of the following are true of stiffness except:

It is equal to the period divided by the frequency

All of the following are true of wavelength except:

Wavelength

All of the following relate to the strength of the sound wave except:

An increase in pulse duration

An increase in pulse repetition frequency would lead to:

Compressions

Areas of high pressure and density are referred to as:

All the above

As a sound wave travels through the human body, the intensity of the sound wave decreases as a result of:

Increases

As imaging depth increases, pulse repetition period:

Decrease

As imaging depth increases, the pulse repetition frequency must:

Reduces the spatial pulse length

Damping of the sound beam:

Inversely related

Density and propagation speed are:

Kilograms per centimeter cubed

Density is typically measured in:

Propagation speed will decrease

If only the density of a medium is increased, then the:

Increases

If pulse repetition frequency increases, then the duty factor:

>40 degrees

If the angle of incidence is 40 degrees, what is the angle of transmission at the interface of medium 1 has a propagation speed of 1320 m/s and medium 2 has a propagation speed of 1700 m/s?

0.1 to 0.8 mm

In clinical imaging, the wavelength measures between:

Millionth

Micro denotes: