Ultrasound Physics I Exam With Correct Questions And Answers
What do waves do? All waves carry energy from one location to another
How does sound travel? Sound travel through a medium, where molecules are alternately compressed
(condensed) and decompressed (rarefied)
What is condensation? Condensation (or compression) is where there is a higher concentration of energy
What is rarefaction? Rarefaction (or decompression) is where the energy is more widely dispersed
What kind of wave is a sound wave? Sound travels in a straght line. Sound waves are longitudinal
What do positive peaks represent on a graph? Condensation
What do troughs represent on a graph? Rarefaction
What determines sound's category? The frequency of the sound or the number of cycles per second
What is Infrasound? frequencies below 20HZ
What is audible sound? Frequencies between 20 HZ and 20,000 HZ
What is ultrasound? Frequencies above 20,000 HZ
What is diagnostic Ultrasound? Frequencies above 1,000,000 HZ
(1,000 KHZ, 1 MHZ)
What is the sound velocity of soft tissue? 1540 m/sec
or 1.54 mm/msec
What properties determine the velocity through a material? The material's stiffness and density
What will a little increase in stiffness do to velocity? Cause a significant increase in velocity
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, Ultrasound Physics I Exam With Correct Questions And Answers
What will an increase in density result in? An increase in density will result in a slight decrease of the velocity.
How does an increase in stiffness affect velocity? Materials that are stiff have a significantly higher velocity of sound
How does frequency affect the velocity of sound? The velocity of sound is NOT affected by frequency.
How does a transducer work? A transducer converts one form of energy into another. It converts electrical energy
into mechanical energy and back into electric energy
What is a piezoelectric element A piezoelectric element, typically a crystal or a man made ceramic unit, is an
element that, when acted upon by energy, will vibrate and produce mechanical
energy
What is the typical force applied to the element? 100 volts
What is pressure? Pressure is the amount of force per unit area
How is pressure measured? in Pascals
What is nomial resonant frequency? the number given to the transducer (ie a 3.5)
What affects the resonant frequency? The thickness of the element.
How does a thinner element affect resonant frequency? The frequency will be higher
How does a thicker element affect resonant frequency? The frequency will be lower
Describe Huygens Principle Sound waves produced by the imaging transducer originate at multiple points on
the surface of a piezoelectric element. Each of these waves produce wavelets that
project off of the waves, and each wavelet has its own wavelets.
What are broadband transducers? Broadband (or multi hertz) transducers can be operated to produce ultrasound
pulses equal to one of multiple selected frequencies. The 3.5 MHz transducer, for
example, can be operated at 2 MHz, 3.5 MHz or 5 MHz
How do Pulse Wave transducers work? A single element cannot produce and receive waves at the same time, so they must
pause the transmission to receive .
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What do waves do? All waves carry energy from one location to another
How does sound travel? Sound travel through a medium, where molecules are alternately compressed
(condensed) and decompressed (rarefied)
What is condensation? Condensation (or compression) is where there is a higher concentration of energy
What is rarefaction? Rarefaction (or decompression) is where the energy is more widely dispersed
What kind of wave is a sound wave? Sound travels in a straght line. Sound waves are longitudinal
What do positive peaks represent on a graph? Condensation
What do troughs represent on a graph? Rarefaction
What determines sound's category? The frequency of the sound or the number of cycles per second
What is Infrasound? frequencies below 20HZ
What is audible sound? Frequencies between 20 HZ and 20,000 HZ
What is ultrasound? Frequencies above 20,000 HZ
What is diagnostic Ultrasound? Frequencies above 1,000,000 HZ
(1,000 KHZ, 1 MHZ)
What is the sound velocity of soft tissue? 1540 m/sec
or 1.54 mm/msec
What properties determine the velocity through a material? The material's stiffness and density
What will a little increase in stiffness do to velocity? Cause a significant increase in velocity
Stuvia.com | New Version
, Ultrasound Physics I Exam With Correct Questions And Answers
What will an increase in density result in? An increase in density will result in a slight decrease of the velocity.
How does an increase in stiffness affect velocity? Materials that are stiff have a significantly higher velocity of sound
How does frequency affect the velocity of sound? The velocity of sound is NOT affected by frequency.
How does a transducer work? A transducer converts one form of energy into another. It converts electrical energy
into mechanical energy and back into electric energy
What is a piezoelectric element A piezoelectric element, typically a crystal or a man made ceramic unit, is an
element that, when acted upon by energy, will vibrate and produce mechanical
energy
What is the typical force applied to the element? 100 volts
What is pressure? Pressure is the amount of force per unit area
How is pressure measured? in Pascals
What is nomial resonant frequency? the number given to the transducer (ie a 3.5)
What affects the resonant frequency? The thickness of the element.
How does a thinner element affect resonant frequency? The frequency will be higher
How does a thicker element affect resonant frequency? The frequency will be lower
Describe Huygens Principle Sound waves produced by the imaging transducer originate at multiple points on
the surface of a piezoelectric element. Each of these waves produce wavelets that
project off of the waves, and each wavelet has its own wavelets.
What are broadband transducers? Broadband (or multi hertz) transducers can be operated to produce ultrasound
pulses equal to one of multiple selected frequencies. The 3.5 MHz transducer, for
example, can be operated at 2 MHz, 3.5 MHz or 5 MHz
How do Pulse Wave transducers work? A single element cannot produce and receive waves at the same time, so they must
pause the transmission to receive .
Stuvia.com | New Version
