Spi chapter 1 questions.

What is pressure measured in?

Pascals or pounds per square

It is described as the ability of an object to resist compression and relates to the hardness of a midium?

Stiffness

All of the following are true of stiffness except

Stiffness and propagation speed are indirectly associated

The typical range of frequency for diagnostic ultrasound imaging is

1 to 20 MHz

Areas of high pressure and density are referred to as

Compressions

As imaging depth increase, the pulse repetition frequency Must

Decrease

The prefix "centi" denotes

Hundredths

Density and propagation speed are

Inversely related

Micro denotes

Millionth

If only the density of a medium is increased then the

Propagation speed will decrease

The clinical imaging, the wavelength measures between

0.1 to 0.8mm

If the amplitude is tripled, the power is increase by

A factor of nine.

Sound is technically a

Mechanical and longitudinal wave

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

Duty factor

All of the of the following are true of wavelength except

It is equal to the period divided by the frequency

Density is typically measured in

Kilograms per centimeter cubed

Which one has the lowest propagation speed?

Lung tissue

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?

Pulse repetition period

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

Rarefaction

Damping of the sound beam

Reduces the spatial pulse length

The change in the direction 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

Refraction

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

Wavelength

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

Wavelength

The duty factor for continuous wave ultrasound is

100%

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

12dB

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

1540 m/s

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

>40degrees

The mayor component of attention is

Absorption

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

All of the above

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

Amplitude

An increase in pulse repetition frequency would lead to

An increase in duty factor

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

Axial resolution

Which one has the highest propagation speed?

Bone

The inertia of the medium describes its

Density

Which of the following determined by the sound source only?

Frequency

As imaging depth increases pulse repetition period

Increases

If pulse repetition frequency increases then the duty factor

Increases

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

Intensity

What is the change in intensity if power decreases by haif

Intensity is halved

What is the change in power if the amplitude triples?

It increases nine times

Transducer have material within them that , when electronically stimulated, produces ultrasound waves. This is most likely some form of

Lead zircon ate titanate

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

Millimeters per microsecond(mm/us)

Spatial pulse length can be calculated by

Multiplying the number of cycles times the wavelength

The attenuation coefficient in soft tissue is equal to

One half of the operating frequency

Pressure is typically expressed in

Pascals

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

Pulse duration

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

Snell's law

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

Wavelength