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ARDMS- SPI Questions and Answers
with Certified Solutions
The horizontal axis, or x-axis ✔✔Runs side to side
The vertical axis, or y-axis ✔✔Runs up and down
Unrelated ✔✔Two items that are not associated
Related or Proportional ✔✔Two items that are associated or affiliated
However, the relationship between the items does not have to be specified
Directly related or Directly proportional ✔✔Two items that are associated such that when one item increases, the other increases
Inversely related or inversely proportional ✔✔Two items are associated such that when one item increases, the other decreases
Reciprocal Relationship ✔✔When two numbers with a reciprocal relationship are multiplied together, the result is one
Reciprocal numbers are inverse because when one increases, the other decreases
For a numerical answer to a question to be comprehensive, it requires a ✔✔Unit
"Increase by a factor" means ✔✔To multiply by that number
"Decrease by a factor" means ✔✔To divide by that number
Scientific or engineering notation is a shorthand manner to represent what types of numbers? ✔✔Very large or very small numbers
A number in scientific notation form with a positive exponent has a value ✔✔Greater than 10
A number in scientific notation form with an exponent of zero has a value ✔✔Between 1 and 10
A number in scientific notation form with a negative exponent has a value ✔✔Less than 1
Symbol: da
Meaning: ten
10 ⌃- 1 ✔✔Prefix: deci
Symbol: d
Meaning: tenth
10 ⌃- 2 ✔✔Prefix: centi
Symbol: c
Meaning: hundredth
10 ⌃- 3 ✔✔Prefix: milli
Symbol: m
Meaning: thousandth
10^- 6 ✔✔Prefix: micro
Symbol: μ
Meaning: millionth
10^-9 ✔✔Prefix: nano
Symbol: n
Meaning: billionth
List all these metric terms in increasing order:
A. mega
B. micro
C. milli
D. hecto
E. deca
F. deci ✔✔micro, milli, deci, deca, hecto, mega
List all these metric terms in decreasing order:
A. nano
B. canti
C. giga
D. kilo
Sound waves are ____________ waves. ✔✔Longitudinal
What is the propagation speed dependent on? ✔✔The medium
Are there any biologic effects on tissue? ✔✔No
Sound waves are identified by ✔✔Oscillations in acoustic variables
What are the three acoustic variables? (With their units) ✔✔pressure - pascals (Pa), density - kg/cm^3, distance - cm, mm
If something other than pressure, density, or distance (particle motion) rhythmically oscillates in a wave, then the wave... ✔✔Is not a sound wave
Sound waves are also known as ✔✔Acoustic waves
What are the seven Acoustic Parameters? ✔✔Period, frequency, amplitude, power, intensity, wavelength, propagation speed
Particles move in a direction that is perpendicular to the direction that the wave propagates in what wave? ✔✔Transverse wave
Particles move in the same direction that the wave propagates in a ____________ wave. ✔✔Longitudinal
When are a pair of waves considered in-phase? ✔✔When their peaks and troughs occur at the same time and at the same location
Considered "in step"
What happens when two waves are out-of-phase? ✔✔Their peaks occur at different times, and so do their troughs
"out of step"
What is interference? ✔✔When more than one beam travels in a medium and arrive at the same location at exactly the same time
These waves lose their individual characteristics and combine to form a single wave
What units are used to report the pressure of a sound beam? ✔✔Pascals, Pa
What describes features of a sound wave? ✔✔Parameters
What is the source of a sound wave? ✔✔The ultrasound system and the transducer
Some parameters are determined by the tissue through which the sound is traveling, also called a __________. ✔✔Medium
What is period? And what is it determined by? ✔✔The time it takes a wave to vibrate a single cycle, or the time from start of a cycle to the start of the next cycle
It is determined by the source
What is frequency? And what is it determined by? ✔✔The number of cycles that occurs in one second
Determined by the sound source only
1 cycle/second = ✔✔1 Hertz
If the frequency of a sound wave is less than _____, it is below the threshold of human hearing and cannot be heard. These are defined as ____________. ✔✔20 Hz, infrasonic
Audible sound waves that humans can hear are frequencies between _______________________. ✔✔20 Hz and 20,000 Hz
What is ultrasound's frequency? ✔✔Greater than 20,000 Hz or 20 kHz
Why is frequency important in diagnostic sonography? ✔✔It affects penetration and image quality
Period and frequency are __________ related to each other. ✔✔Inversely
When two reciprocal parameters are multiplied together, the result is: ✔✔ 1
What is power determined by? And can it be changed? ✔✔Determined by the sound source only
It CAN be changed
How are amplitude and power related? ✔✔Both describe the size, or magnitude of a wave. When power increases, so does amplitude
Power is proportional to... ✔✔amplitude^
What is intensity? ✔✔The concentration of energy in a sound beam Intensity = Power/area
What is intensity determined by? And is it adjustable? ✔✔Sound Source
Yes, it is adjustable
How is intensity related to power and amplitude? ✔✔Intensity is proportional to power
Intensity is proportional to amplitude^
What is the distance or length of one complete cycle called? ✔✔Wavelength
What is wavelength determined by? And is it adjustable? ✔✔Both the medium and source
No, it is not adjustable
What is the relationship between wavelength and frequency? ✔✔As long as a wave remains in one medium, wavelength and frequency are inversely related
As frequency increases, wavelength decreases. The lower the frequency, the longer the wavelength
What is the wavelength of 1 MHz sound in soft tissue? ✔✔1.54 mm
What is the wavelength of other frequency sound waves in soft tissue? ✔✔Sound with a frequency of 2 MHz has a wavelength of 0.77 mm in soft tissue. 1.54mm/2 = 0.77 mm
What is the wavelength equation? ✔✔wavelength = (1.54mm/μsec)/(frequency)
Why is wavelength important in diagnostic ultrasound? ✔✔Wavelength plays an important role in image quality
What is the speed of sound in Blood? ✔✔1,560 m/s
What is the order for speed of sound from lowest to highest in Water, Metals, and Air? ✔✔Air, Water, Metals
What determines the speed of sound in that medium? ✔✔Stiffness, density
What describes the ability of an object to resist compression? ✔✔Stiffness; A stiff material will retain its shape if it is squeezed; whereas a non-stiff material will change its shape
How does stiffness affect speed? ✔✔Stiffness and Speed are directly related
As materials become stiffer, the speed of sound in the material increased
Non-stiff media are described as... ✔✔Elastic or compressible
What describes the relative weight of a material? ✔✔Density
How does density affect speed? ✔✔Density and speed are inversely related. As materials become more dense (heavier), the speed of sound in the material decreases
When Stiffness increases, Speed ______ ✔✔Increases
When Density Increases, Speed ________ ✔✔Increases
What two parameters are reciprocals? ✔✔Period and Frequency
What is the only parameter that is determined by the medium? ✔✔Speed
What is wavelength decided by? ✔✔Both the Sound Source and the Medium
What are the units of:
wavelength -
frequency -
intensity -
propagation speed -
propagation speed - medium
period - source
power - source
amplitude - source
Which of the following cannot be changed by the operator?
wavelength
frequency
intensity
propagation speed
period
power
amplitude (initial) ✔✔Wavelength, frequency, propagation speed, period
True or False. A wave with a frequency of 15,000 MHz is ultrasonic. ✔✔True (any wave
20,000 hertz)
True or False. If the amplitude of a wave is increased to 3 times its original value, the intensity in increased by 6 times. ✔✔False (if we triple amplitude, we increase intensity by a factor of nine)
True or False. If the power of a wave is halved ,the intensity is reduced to one-fourth its original value. ✔✔False (intensity is the power/area, if we halve the power we will halve the intensity)
True or False. Propagation Speed increases as Frequency increases. ✔✔False (frequency is unrelated to speed)
Medium 1 has a density of 9 and a stiffness of 6. Medium 2 has a density of 8 and a stiffness of
- In which medium will sound travel slower? ✔✔Medium 1: Since both media have the same stiffness, the medium with the greater density has the lower propagation speed
If the power in a beam is 1 watt and the area is 5cm^2, what is the beams intensity? ✔✔0. W/cm^
If intensity remains the same while the power had doubled, what has happened to the beam area? ✔✔Doubled (if intensity stays the same, whatever happens to power also has to happen to area)
