Review Chapters 1-6

The velocity of sound in human soft tissue is assued to be a constant. If you employ a 1-MHz transducer, what is the wavelength of the sound? a. 0.11 mm b. 0.20 mm c. 0.025 mm d. 1.54 mm

1.54 mm

The average propagation speed in human soft tissue is ______. a. 1.54 cm/us b. 1.54 mm/us c. 15.4 m/s d. 1.54 m/s

1.54 mm/us

two sound pulses travel through the same medium. One wave's frequency is 2 MHz and the other is 10 MHz. Which sound wave has a longer period? a. the 10 MHz pulse b. the 2 MHz pulse c. neither pulse d. cannot be determined

2 MHz pulse

What is the range of frequencies emitted by transducers used in ultrasonic imaging? a. 1 to 3 MHz b. 1 to 1,000 kHz c. -10,000 to +10,000 Hz d. 2,000,000 to 10,000,000 Hz

2,000,000 to 10,000,000 Hz

what is the pulse duration of a four-cycle pulse in a period of 0.5 a. 0.2 b. 2.0 c. 1.25 d. 0.125

2.0

20 kHz is equal to _____Hz. a. 200 b. 2000 c. 20,000 d. 200,000

20,000

The attenuation coefficient for soft tissue using a 10-MHz transducer is ______. a. 5 db/cm b. 5dB/mm c. 10 dB/cm d. 10 dB/mm

5 dB/cm

How many milliliters are contained in a jar filled with 5 liters of fluid? a. 5 b. 5,000 c. 500 d. 0.005

5,000

Compare two sound waves, A and B. The frequency of wave A is one-third that of wave B. How does the period of wave A compare with the period of wave B? a. A is one-third as long as B b. A is the same as wave B c. A is three times as long as B d. cannot be determined

A is three times as long as B

The amplitude of an acoustic wave is increased. Which of the following will most likely remain unchanged? a. power b. frequency c. period d. intensity e. A and B f. B and C g. C and D

B and C

Duty factor equals? a. PD/PRP b. C/F c. 1/P d. VxT

PD/PRP

Bioeffects intensity measurements use what intensity? a. SPTA b. SAPA c. SPPA d. SATA

SPTA

sound is best described as ______ a. a series of compressions and rarefactions b. a transvere wave c. a wave that humans can hear d. an oblique displacement of acoustic energy

a series of compression and rarefactions

______ is the dominant factor contributing to attenuation of ultrasound in soft tissue. a. absorption b. backscattering c. reflection d. range

absorption

which of these media has the greatest attenuation and the slowest speed? a. bone b. tendon c. fat d. air

air

What is the amount of attenuation per centimeter that a sound wave undergoes called? a. beam uniformity coefficient b. attenuation coefficient c. attenuation d. duty factor

attenuation coefficient

A sound wave reached a rough or irregular border between two media. Under these explicit circumstances, which process is most likely to occur? a. backscatter reflection b. specular reflection c. Rayleigh scattering d. refraction

backscatter reflection

If sound doesn't travel at 1,540 m/sec in a medium, then the medium _______ a. must be soft tissue b. may be soft tissue c. cannot be soft tissue

cannot be soft tissue

select the sequence that appears in increasing order. a. mega, kilo, hecto, milli, giga b. nano, milli, micro, deci, deca, mega c. centi, deci, deca, hecto d. milli, hecto, centi, deci, nano, giga

centi, deci, deca, hecto

A pair of waves are in phase. What occurs when these waves interfere? a. reflection b. constructive interference c. refraction d. destructive interference

constructive interference

If frequency increases, period will _____ a. increas b. decrease c. remain unchanged d. none of the above

decrease

If intensity remains the same while the power is doubled, what has happened to the beam area? a. quadrupled b. doubled c. halved d. unchanged

doubled

The fraction of time that pulsed ultrasound is on is called _____. a. pulse repetition period b. duty factor c. period d. spatial pulse length

duty factor

what do waves transfer from one location to another? a. matter b. molecules c. energy d. coodies

energy

Attenuation increases with increasing _______ a. wavelength b. frequency c. power d. pressure

frequency

By adjusting the imaging depth the sonographer changes all these except a. pulse repetition period b. frequency c. pulse repetition frequency d. duty factor

frequency

_________ is the amount of complete cycles per second a. wavelength b. period c. frequency d. propagation speed

frequency

which is not an acoustic variable? a. pressure b. frequency c. density d. particle vibration

frequency

As a general rule, which of the following lists media in increasing order of propagation speeds? a. gas, solid, liquid b. liquid, solid, gas c. solid, liquid, gas d. gas, liquid, solid

gas, liquid, solid

Stiffer media have _______ sound speeds. a. lower b. higher c. stiffness doesn't change the propagation speed d. sound cannot propagate through the stiffer media.

higher

The speed of sound traveling through bone is _______ soft tissue a. higher than b. lower than c. equal to d. cannot be determined

higher than

In oblique incidence the ___ and _____ angles are always equal. a. transmitted; reflected b. normal; transmitted c. incidence; reflection d. incidence; transmitted

incidence; reflection

If the beam area decreases, the intensity will ____. a. decrease b. remain unchanged c. increase d. quadruple

increase

Doubling the amplitude causes? a. increased frequency by a factor of 1/4 b. doubles the intensity c. increases propagation speed d. increases power by a factor of 4

increases power by a factor of 4

If the power in an ultrasound beam is unchanged, while at the same time, the beam area doubles, then the beams intensity: a. doubles b. is halved c. is quartered d. remains the same

is halved

Wavelength is the ____ over which one cycle occurs. a. time b. length c. area d. all of the above

length

Infrasound is defined as a sound with a frequency of _______ a. greater than 20,000 kHz b. less than 20 Hz c. greater than 10 MHz d. less than 0.02 MHz

less than 20 Hz

which of the following characteristics will create the fastest speed of sound? a. high density, high stiffness b. low density, high stiffness c. high density, low stiffness d. low density, low stiffness

low density, high stiffness

Shallow imaging requires all of these except? a. less listening time b. shorter PRP c. lower PRF d. higher duty factor

lower PRF

which term is the reciprocal of Mega? a. nano b. kilo c. macro d. micro

micro

Two sound waves with frequencies of 5 and 3 MHz, travel to a depth of 8cm in a medium and then reflect back to the surface of the body. Which acoustic wave arrives first at the surface of the body? a. the 5 MHz wave b. the 3 MHz wave c. neither

neither

The final amplitude of an acoustic wave is reduced to one-half of its original value. The final power is ______ the original power. a. the same as b. one half c. double d. none of the above

none of the above

Using a particular ultrasound system, which of the following cannot be changed by the operator? a. amplitude b. period c. intensity d. power

period

Impedance is equal to density multiplied by _______. a. propagation speed b. wavelength c. path length d. stiffness

propagation speed

Regions of lower pressure and density are called ______ a. compressions b. rarefactions c. longitudinal waves d. acoustic variables

rarefactions

For perpendicular incidence and equal impedances between media, there is no _____ and the ____ intensity equals the incident intensity. a. transmission; reflected b. reflection; transmitted c. transmission; transmitted d. reflection; reflected

reflection; transmitted

In oblique incidence the sound ____ at a boundary between two media where propagation speeds are different. a. transmitted b. refracted c. reflected d. attenuated

refracted

attenuation encompasses absorption, reflection, and _______ a. transmission b. scattering c. retraction d. ablation

scattering

Which parameter is determined by the sound source and the medium? a. pulse duration b. pulse repetition period c. duty factor d. spatial pulse length

spacial pulse length

Propagation speed is primarily determined by the ____ of the medium. a. density b. thickness c. stiffness d. water

stiffness

The speed at which a wave travels through a medium is determined by: a. the sound wave's properties only b. the medium's properties only c. properties of both wave and medium d. none of the above

the mediums properties only

what determines the initial intensity of an ultrasound beam? a. the source of the sound wave b. the medium through which the sound travels c. both A and B d. neither choice A nor B

the source of the sound wave

Period is the ______ it takes for one ____ to occur. a. time; cycle b. time; wavelength c. frequency; cycle d. time; class

time; cycle

Intensities for pulse-mode operation vary in both _____ and _____. a. amplitude; propagation speed b. stiffness; density c. time; space d. time; stiffness

time; space

Snell's law relates the _____ beam direction to the incident beam direction and the speeds of sound in the two materials forming the interface. a. scattering b. rarefaction c. reflected d. transmitted

transmitted

what are the units of pulse duration? a. units of frequency (Hz, etc.) b. msec only c. units of time (sec, years, etc) d. units of distance (feet, etc)

units of time (sec, years, etc)

The propagation speeds of ultrasound waves in muscle, liver, kidney and blood are _____ a. exactly the same b. very similar to each other c. vastly different

very similar to each other

What are the units of intensity? a. watts b. watts/cm c. watt/cm2 d. dB

watts/cm2