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103 Cards in this Set
- Front
- Back
Which of the following waves has the longest period?
A: 2MHz B: 4,000 Hz C: 6 Hz D: 1kHz |
C: 6 Hz. the wave with a fq. of 6 Hz has the longest period. period and fq have an invers relationship
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Which of the following periods has the longest frequency?
A: 8 s B: 80 microsecs C: 8 Ms D 800 ks |
B: 80 microsecs is the period that has the highest fq. period and fq have an invers relationship
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Identify all the waves that are inaudible (more than one answer may be correct)
A: 4 MHz B: 400 kHz C: 28 Hz D: 2 Hz |
A B D
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Which of the following waves has the shortest period?
A: 12 kHz B: 6,000 Hz C: 205 Hz D: 1 kHz |
A: 12 kHz the highest freq. has the shortest period
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Of the 4 waves whose periods are listed below, which has the lowest frequency?
A: 8 s B: 80 microseconds C: 8 Ms D: 800 ks |
C: 8 Ms the wave with the longest period has the lowest freq.
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What are the units of wavelength?
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millimeters
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What are the units of frequency?
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Hz
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What are the units of intensity
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W/cm^2
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What are the units of propagation speed?
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meters/second
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What are the units of period?
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second
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What are the units of power?
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watts
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Does the medium or the sound source determine the parimeters for wavelength?
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both
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Does the medium or the sound source determine the parimeters for frequency?
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sound source
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Does the medium or the sound source determine the parimeters for intensity (initial)?
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sound source
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Does the medium or the sound source determine the parimeters for propagation speed?
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medium
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Does the medium or the sound source determine the parimeters for period?
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sound source
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Does the medium or the sound source determine the parimeters for power (initial)?
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sound source
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Does the medium or the sound source determine the parimeters for amplitude?
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sound source
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Using a particular ultrasound system and transducer can wavelength be changed by the operator?
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no
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Using a particular ultrasound system and transducer can frequency be changed by the operator?
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no
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Using a particular ultrasound system and transducer can intensity be changed by the operator?
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yes
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Using a particular ultrasound system and transducer can propagation speed be changed by the operator?
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no
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Using a particular ultrasound system and transducer can period be changed by the operator?
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no
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Using a particular ultrasound system and transducer can power be changed by the operator?
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yes
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Using a particular ultrasound system and transducer can amplitude (inital) be changed by the operator?
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yes
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If the power of a beam is 1 watt and the area is 5 cm^2 what is the beam's intensity?
A; 5 W/cm^2 B; 1 W/cm^2 C; 0.2 W/cm^2 D; 1 watt |
C; 0.2 W/cm^2 Intensity has units of W/cm^2. We must find out how many watts and divide them by the number of cm^2. 1 watt. area is 5cm^2. Thus the intensity is 1/5 or 2 W/cm^2
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if intensity remains the same while the power is doubled, what happened to the beam area?
A; quadrupled B; doubled C; halved D; unchanged |
B; doubled If intensity remains unchanged, then whatever happens to power must also happen to area. In this case, power has doubled, therefore area must have doubled as well
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A sound beam travels a total of 10 cm in 2 seconds. What is the speed of sound?
A; 10 cm/sec B; 2 cm/sec C; 5 cm/sec D; 0.2 cm/sec |
C; 10 cm/2 sec= 5 cm/sec
speed=distance/time |
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What is the wavelength of 3 Mhz sound in soft tissue?
A; 0.51 m B; 0.51 km C; ; 0.51 mm D; ; 0.51nm E; 0.51 micrometers |
C; 0.51 mm. In soft tissue the wavelength is 1.54 mm divided by frequency in MHz
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What is the wavelength of a wave with an unknown frequency in soft tissue?
A; 0.51 microseconds B; 0.51 m/s C; 0.51 pascals D; 0.51watts E; 0.51 mm |
E is the only answer with units of distance
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which of the following are considered acoustic variables? (more than one answer may apply)
A; frequency B; density C; particle motion D; temparture E; period F; pressure |
Density particle motion, pressure
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which of the following are considered acoustic parimeters? (more than one answer may apply)
A; frequency B; density C; distance D; pressure E; period |
frequency, period
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the effects of tissue on sound waves are called?
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acoustic propagation properties
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the effects of a medium on an ultrasound wave are called?
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acoustic propagation properties
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the effects of the medium an ultrasound are called?
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acoustic propagation properties
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how are the acoustic velocity and density related?
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inversely
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how are the elasticity and speed of sound and density related?
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inversley
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how are the acoustic velocity and comperssibilty related?
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inversley
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how are the stiffness and souind speed related?
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directly
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how are the freq and sound speed related?
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unrelated
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how are the freq and intensity related?
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unrelated
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how are the power and freq related?
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unrelated
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how are the wave length and intensity related?
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unrelated
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how are the wave length and freq related?
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inversly
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how are the freq and period related?
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inverse f=1/p or p=1/f
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which of these four values for pulse rep freq would have the longest pulse rep period?
A; 2kHz B; 4000 hZ C; 6 hz D; 1 kHz |
four pulses have PRP as listed below which have the highest PRF?
A; 8 sec B; 80 millisec C; 5 ms D; 400 ks |
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C 6 Hz
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C; 5 ms the smaller seconds are the
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four waves have PRP as listed below, which has the lowest PRF
A; 8s B 80 microseconds C 8000 ns D 800 ms |
A 8000 ns the pulse with the longest pulse duration will have the lowest freq
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2 waves can have indentical PRF even if their pulsePRP are different. True or false
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false. 2 waves can never have idnetical PRFs if their PRP are different
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2 waves can identical PRF's even if their periods are different T F?
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true period and pulse freq are unrelated
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2 waves can have idnetical PRF even if thier freq are diff.
T OR F? |
true freq and PRF are unrelated
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PRF and PRP are determined only by the imaging depth?
T F? |
true, this is a very important concept to understand
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if all other facxtors remain unchanged, what happend to the duty factor (increase, decrease, same) when the PRF increases?
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increases
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if all other factors remain unchanged. what happens to the duty factor (increas, decrease, unchange) when imaging depth increases?
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decreases
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if all other factors remain unchanged. what happens to the duty factor (increas, decrease, unchange) when PRP increases?
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decreases
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if all other factors remain unchanged. what happens to the duty factor (increase, decrease, unchange) when the sonographer uses an new transducer with a longer pulse duration?
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increases
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what is the duty factor if the pulse duration is 1 microsecond and the PRP is 1 ms?
A 100% B 0,1 C 01 D 0.001 |
D 1,000/1,000,000
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Which of the following terms does not belong with the others?
A high duty factor B shalow imaging C low PRF D short PRP |
C low PRF is associated with deeper imaging the other 3 choices are all associated with shallow imaging
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which of the following terms doesn't belong with the others/
A low duty factor B shallow imaging C Low PRF D long PRP |
B shallow imaging does not belong the other 3 choices are all associated with deeper imaging
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PRF is the reciprocial of what?
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PRP
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by changing the imaging depth, which of the following does the operator also cange (more than 1 may be correct)
A PRF B duty factor C propagaiton speed D PRP E amplitude F SPL |
A PRF
B duty factor C PRP |
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the speed of a 5 MHz CW is 1.8 km/sec. the wave is then pulsed with a duty factor of 0.5 calculate the new propagation speed
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the propagtion speed for PW is the same as CW at 1.8 Km/s. It depends only upon the medium.
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what is the duty factor if the pulse duration is 1 microsecond and the PRP is 1 ms?
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the duty factor is 0.001 or 10^-3 10^-6/10^-3
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what is the duty factor if the Pulse duration is 1 ms and the PRP is 1 sec?
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0.001 or 0.1% 0.001/1=0.001
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a reduction in the intensity of a sound beam to 1/2 of its orginal value is ______dB
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-3dB
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a reduction in the intensity of a soundbeam to 1/4 of iths orginal value is _______dB?
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-6dB
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-10dB means that the intensity is reduced to _____ of its orginal value?
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1/10
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dB is mathmatical representation with a ______ scale
A logarithmic and relative B division and relative C longitudinal and relative D logarithmic and ablsoute |
A
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T or F? we need on intensity to calculate dB's?
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false, we need 2 intensities
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a wave's intensity is 2 mW/cm^2. there is a change of +9dB. what is the final intensity?
A 6mW/Cm^3 B 2mW/Cm^2 C 16mW/Cm^2 D 16microW/Cm^2 |
C
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every 3 dB change means that the intensity will __________
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double
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a reduction in the intensity of a sound beam to 1/2 of its orginal value is ____________dB
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-3 dB
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a reduction in the intensity of a sound beam to 1/4 of its orginal value is ____________dB
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-6 dB
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-10 dB means that the intensity is reduced to ____ or its orginal value
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1/10
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dB is a mathmatical represenation with a ______
scale A logarithmic and relative B division and relative C longitudinal and relative D logarithmic and absolute |
A
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T or F? we need only one intensity to calculate dB
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F we need 2
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A wave's intensity is 2 mW/cm^2. there is a change of +9 dB. what is the final intensity?
A 6mW/cm^3 B 2mW/cm^2 C 16mW/cm^2 D 16microW/cm^2 |
C
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every 3 dB change means that the intensity will ________
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double
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every 10dB change means that the intensity will ________
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increase 10 times
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if the final intensity of a sound beam is more than the final intensity, then the gain in dB is _____ (+or -)
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+
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if the final intensity of a sound beam is less than the final intensity, then the gain in dB is _____ (+or -)
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+
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as the path length increses, the attenuation of ultrasound in soft tissue _______
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increases
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attenuation in lung tissue is ( les, greater than or the same) attenuation in soft tissue?
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greater than
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attenuation in bone is _______ attenuation in soft tissue?
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greater than
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attenuation in air is ______ than soft tissue?
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greater than
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what are the units of attenuation?
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dB
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in a given medium, attenuation is unrealted to the speed of sound? T or F?
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true annenuation and propagtion speed are unrealated
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what is the relationship between ultrasound freq and the attenuation coefficent in soft tissue?
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in soft tissue, the attenuation coeffieient in dB per centimeter is approx 1/2 of the Ultrasound freq in MHz
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what aer the units of the half-value layer thickness?
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distance, centimeters
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as freq decreases, depth of penetration _____
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increases
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as path lenght increases the half bondry layer _____
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remains the same
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impedence is a characteristic of ________
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.only the medium
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as the pathe length increses, the attenuation coeffiecent of ultrasound in soft tissue ( decrease, increase, same)
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same
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acoustic impedence Z = ___X____
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Density P X propagation speed C
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2 media A and B have the same densities the speed of sound in the medium A is 10% higher than B which medium has the higher acoustic impedence?
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medium A 's acoustic impedence is higher. recall that Z =P X C
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impedence is important in ____at boundries
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reflections
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a pulse of ultrasound is prpagating in soft tissue like liver. the pulse strkes a boundary with a differernt soft tissue at normal incidence? what portion of the intensity is reflected back toward the transducer? why?
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a small percentage less than 1 % the difference in Z of 2 soft tissues directly determines the inetnsity refletion coeffecent
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sound is traveling in a medium and strikes a boundry with normal incidence. if 63% of the waves intensity is feflected back, what percent is transmitted?
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37%
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a pulse of ultrasound is propagating in bone and strikes an interface at 90 degrees. A giant reflection is created
-from these facts alone what can be said about the impedence of bone? |
nothing can be stated about the inpedence of bone or soft tissue givin the info
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sound is traveling in a medium and orthogonally strikes a boundry with a different medium. Althogh the media are very different no reflection is created, How can this be?
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with normal incidence, reflections occur only when the impedences of the 2 media at the interface are different
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sound is traveling from bone to soft tissue. the Z of the media differ siginfcantly and 90% of the beams intensity is reflected. what % of the intensity is transmitted?
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100% must be accounted for so 10 % must be transmitted
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a pulse of ultrasound propagates in soft tissue such as liver. The pulse strikes a soft tisssue-soft tissue interface with oblique incidence. Some of the sound energy is transmitted. To what extend is the transmitted beam refracted?
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the transmitted beam undergoes little to no refraction. a transmitted beam is refracted when the propagation speeds are different. because the tissues on bothe sides are soft tissues. their speeds are nearly identical
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a sound pulse travels in medium 1 and strikes an interface with antoher tissue, Medium 2 @ 30 degrees. the angle of transmission is 10 degrees. from these facts what can be said about
-the speed of sound in medium 1 |
given only this info, we can say nothing about the speed of sound in mdeium 1 or 2. However, because the beam refracted significantly (a 20 degree change) the speeds of the 2 media are very different.
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