# SPI Reiview

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The flashcards below were created by user monkies on FreezingBlue Flashcards.

1. what does an ellipse measure?
area
2. length
cm, feet
3. area
cm^2, ft^2
4. volume
cm^3, ft^3
5. percent
is not a unit
6. "increase by a factor of" means
multiply
7. decrease by a factor of means
divide
8. 10^9 = billion
giga = G
9. 10^6 = million
mega = M
10. 10^3 = thousand
kilo = k
11. 10^2 = hundred
hecto = h
12. 10^1 = ten
deca = da
13. 10^-1 = tenth
deci = d
14. 10^-2 = hundreth
centi = c
15. 10^-3 = thousandth
milli = m
16. 10^-6 = millionth
micro = μ
17. 10^-9 = billionth
nano = n
18. acoustic propagation properties
the effects of the medium upon the sound wave
19. biologic effect
the effects of the sound wave upon the biologic tissue
20. sound
• a type of wave that carries enery, not matter from place to place
• must travel through a medium
• is mechanical, longitudinal wave
• travels in a straight line
21. compressions
are areas of increased pressure or density
22. rarefactions
are areas of decreased pressure or density
23. three acoustic variables
• pressure = concentration of force w/i area force / area units= pascal (Pa)
• density = concentration of mass w/i volume units = kg/cm^3
• distance = measure of particle motion units = cm, ft, miles
24. transverse wave
particles move in a perpendicular direction (right angles or 90) to the direction of the wave
25. sound is longitudinal wave
particles move in the same direction as the wave
26. acoustic parameters
• period
• fequency
• amplitude
• power
• intensity
• speed
• wavelength
27. period
• the time required to complete a single cycle (the start of a cycle to the start of the next)
• units = any unit of time
• determines by = sound source
• can not be changed by sonographer
28. frequency
• number of certain events that occure in a particular time duration
• units = per second, 1/second = Herts (Hz)
• determined = sound source
• can not be changed by sonographer
• frequency affects penetration and axial resolution
29. ultrasound
• a wave with a frequency exceeding 20,000Hz (20 kHz)
• frequency is so high that is not audible
30. audible sound
heard by man, frequencies btwn 20Hz and 20,000Hz
31. infrasound
• sound with frequencies less than 20Hz
• frequency is so low that is not audible
32. frequency and period
• are reciprocals
• frequency (Hz) x period (sec) = 1
• period (sec) = 1/ frequency (Hz)
• frequency (Hz) = 1/period (sec)
• when one goes down the other goes up
33. Three bigness parameters
• amplitude
• power
• intensity
34. amplitude
• the difference btwn the average value and the maximum value of an acoustic variable. the variation of an acoustic variable
• units = same as acoustic variables
• pressure=pascals
• density=grams/cubic cm
• particle motion=cm,inches,units of distance
• may be expressed in decibels (dB)
• determined by sound source (initially)
• can be changed by sonographer
35. power
• the rate that work is performed, or the rate of energy transfer
• units = watts
• determined by sound source (initially)
• can be changed by sonographer
36. power & amplitude
power is porportional to the wave's amplitude squared

• ex: if amplitude is tripled, the power is increase by a factor of nine:
• 3 x 3 = 9
37. intensity
the concentration of energy in a sound beam. the beam's power devided by the beam's cross-sectional area. intensity depends upon bothe the power and the cross-sectional area of the beam

### Card Set Information

 Author: monkies ID: 67978 Filename: SPI Reiview Updated: 2011-02-22 04:23:21 Tags: Physics Folders: Description: Edelman Show Answers:

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