Chapter 2 Flashcards
Acoustic propagation properties
The effects of the medium upon the sound wave.
Biologic effects
The effects of the sound wave upon the biologic tissue through which it passes.
Acoustic Variables (changes)
Pressure - concentration of fource in an area
Density - concentration of mass in a volume
Distance - measure of particle motion
Acoustic Variable (change)
Pressure
pascals (Pa)
Acoustic Variable (change)
Density
kg/cm^3
Acoustic Variable (change)
Distance
cm, mm
Acoustic Parameters( features)
Describe sound waves
Period Frequency Amplitude Power Intensity Wavelength Propagation speed
Transverse Waves
Particles move in a direction that is prependicular (right angles) to the direction that the wave propagates.
Longitudinal waves
Particles osculate in the same direction that the wave propagates.
Sound is a longitudinal wave.
In - Phase Wave
A pair of waves are considered in-phase when their peaks (maximum values) or troughs (minimum values) occur at the same thime and at the same location.
Out - of - Phase Wave
When two waves are out-of-phase their peaks occur at different times and so do their troughs.
Interference
More than one sound beam may travel in a medium and, on occasion, multiple beams may arrive at an identical location at exactly the same time. The waves lose their individual characteristics at that moment and combine to form a single wave.
