Ultrasound Physics 3&4

as an ultrasound wave travels through the body, its amplitude usually.

decreases

as sound travels in the body, what typically happens to the intensity of the wave

decreases

what happens to the pulse repetition period if the sonographer decreases the maximum imaging depth achieved in an ultrasound scan

decreases

The sonographer has the ability to alter the period of an ultrasound wave that is produced by a basic transducer.

false

with standard pulses, the frequency of the ultrasound change significantly as the wave propagates through the body

false

when the power in an acoustic beam is doubled and the cross-sectional area of the beam is halved, then the intensity of the beam is

four time larger

_________is the reciprocal of period

frequency

what term describes the number of cycles that an acoustic variable completes in a second

frequency

as a general rule, which of the following lists media in increasing order of propagation speeds

gas, liquid, solid

ultrasound is defined as a sound with a frequency of

greater than 0.02 Mhz

what happens to the intensity of an ultrasound beam when the beams cross sectional area remains unchanged while the amplitude of the wave triples

increases ninefold

what happens when the power in an ultrasound beam is unchanged, and at the same, the beam area doubles

is halved

which of the following units are appropriate to describe the period of an acoustic wave? More than one answer may be correct

minutes and microseconds

the pulse duration is expressed in the same units as the ______

period

what is the pulse duration equal to

period multiplied by the number of cycles in the pulse

the intensity of an ultrasound beam is defined as the ____in a beam _______by the ______of the beam.

power, divide, area

with standard ultrasound imaging, what happens to the period of a wave as it propagates?

remains the same

in diagnostic imaging what establishes the pulse repetition frequency

the source of the sound

what determines the pulse duration

the source of the wave

which of the following correctly describes pulse repetition period

the sum of the pulses "on" time and the listening "off" time

what determines period of an ultrasound wave.

the transducer

what determines the initial amplitude of an ultrasound wave

transducer

what establishes the frequency of an ultrasound wave

transducer

if the power of the beam is tripled while the cross sectional area of the beam remains the same the intensity

triples

if the period of two waves are the same, then the frequencies of the waves must also be the same

true

the pulse duration o fan ultrasound and transducer system does not change significantly as long as the system components remain unchanged

true

with standard diagnostic imaging instrumentation, the sonographer has the ability to vary the amplitude of a sound wave produced by the transducer

true

what are the units of intensity

watts/cm2

which of the following best describes the spatial pulse length

wavelength multiplied by the number of cycles in the pulse

Typically as an ultrasound wave travels through soft tissue the powernof the wave

decreases

which of the following terms best describes the relationship between frequency and wavelength for sound traveling in soft tissue

inverse

infra-sound is defined as a sound with a frequency of

less than 10 Mhz

two transducers send ultrasound pulses into soft tissue. one transducer emits sound with a 4 Mhz frequency, and the other produces sound at 6 Mhz frequency. Each pulses contains 4 cycles. Which has a greater spatial pulse length?

the 4 Mhz pulse

what is the wavelength of 10 Mhz sound in soft tissue

0.15mm

what is the wavelength of 2 Mhz sound in soft tissue

0.77 mm

the amplitude of an acoustic wave decreases from 27 pascals to 9 pascals. If the initial power in the wave was 27 watts, what is the waves power

3 watts

when a sonographer increases the maximum imaging depth during an exam, what happens

PRF decreases

Using a specific transducer, what happens to the spatial pulse length does not change as long as the components of the ultrasound system are the same

Remains the same

While imaging soft tissue, the spatial pulse length does not change as the components of the ultrasound system are the same

True

the wavelength of an ultrasonic wave is determined by

both A and B sound source, medium through which wave