# Shared Flashcard Set

## Details

Ultrasound Physics
Properties of Sound Waves
35
Physics
05/09/2014

Term
 Giga & Nano (G & n)
Definition
 Billions & Billionths
Term
 mega & micro   (M &    )
Definition
 millions & millionths
Term
 kilo & milli (k & m)
Definition
 thousands & thousandths
Term
 hecto & centi (h & c)
Definition
 hundreds & hundreths
Term
 deca & deci (da & d)
Definition
 tens & tenths
Term
 Sounds travels in a _______ line.
Definition
 Straight
Term
 Sound waves are ________ waves.
Definition
 Longitudinal
Term
 Areas of compression on a sound wave are:
Definition
 Squeezed Together
Term
 A rarefied area of a sound wave is:
Definition
 Stretched Apart
Term
 Acoustic Variables
Definition
 Pressure (Pascals, Pa) Density (kg/cm ) Distance (cm, mm)
Term
 Pressure
Definition
 Concentration of force in an area Units: Pascals (Pa)
Term
 Density
Definition
 Concentration of mass in a volume Units: kg/cm
Term
 Distance
Definition
 Measure of a particle motion Units: cm, feet, mile...
Term
 What is an Acoustic Parameter?
Definition
 A characteristic that describes a sound wave
Term
 What are the 7 Acoustic Parameters?
Definition
 Period Frequency Ampitude Power Intensity Wavelength Propagation Speed
Term
 Transverse Wave
Definition
 Particles move in a direction that is perpendicular to the direction the wave propagates.
Term
 Longitudinal Wave
Definition
 Particles move in the same direction that the wave propagates   Sound is a Longitudinal Wave
Term
 Out-of-Phase Waves
Definition
 When two waves peaks occur at different times, resulting in destructive interference.
Term
 In-Phase Waves
Definition
 When a pair of waves peaks occur at the same time and location, resulting in Constructive Intereference
Term
 Constructive Interference
Definition
 The interference of a pair of in-phase waves that results in a single wave of greater amplitude.
Term
 Destructive Interference
Definition
 The interference of a pair of out-of-phase waves that results in a single wave of lesser amplitude.
Term
 Period
Definition
 The time it takes a wave to complete one cycle. Units: Time (microseconds, s..) Typical Values: .06 to .5 microseconds (   ) Determined By: Source Adjustable: NO
Term
Definition
Term
 Frequency
Definition
 The number of cycles that occur in 1 second. Units: Hz (per second) Typical Values: 2 MHz to 15 MHz (Imaging) Determined by: Source Adjustabe: NO
Term
 Infrasound
Definition
 Less than 20 Hz
Term
 Audible Sound
Definition
 Between 20 Hz and 20 kHz (20,000 Hz)
Term
 Ultrasound
Definition
 Greater than 20 kHz   *Cannot image under 2 MHz (2 million Hz)*
Term
 Period and Frequency are ______ related.
Definition
 Inversely   As FQ increases, Period decreases. As FQ decreases, Period increases
Term
 Preiod and Frequency are _______.
Definition
 Reciporicals   Period x Frequency = 1
Term
 What is the meaing of a sound wave with a frequency of 100 Hz?
Definition
 A frequency of 100 Hz means there are 100 cycles per second.
Term
 Three "Bigness" Parameters
Definition
 Amplitude Power Intensity
Term
 Amplitude
Definition
 The "bigness" of a wave. The difference between the max value and the average value of an acousitc variable. Units: Pa, decibels (dB), density (g/cm ) Typical Values: 1 million Pascals (1MPa) to 3Mpa. Determined by: Source Adjustable: Yes
Term
 Power
Definition
 The rate at which work is performed.   Units: Watts Typical Values: .004 watts to .090 watts (4 to 90 milliwatts) Determined by: Sound Source Adjustable: Yes
Term
 How are Power and Amplitude related?
Definition
 Power is proportional to the amplitude squared.
Term
 Intensity
Definition
 Concentration of energy in a sound beam.   Beams Power / beams cross sectional area Units: W/cm Typical Values: .01 to 300 W/cm Determined by: Source Adjustable: Yes
Supporting users have an ad free experience!