Ultrasound Physics Ch 2

media

biologic tissue

all wave ___ ___ from one location to another

carry energy

sound is a ____ wave

longitudinal mechanical

sound travels through a medium where molecules are:

compressed and rarefied

sound travels in a:

straight line

acoustic propagation properties

effect of the medium upon the sound wave

biologic effects

effects of the sound wave upon the biologic tissue through which it passes

three acoustic variables

pressure

density

distance

pressure

concentration of force in an area

units: Pa

density

concentration of mass in a volume

Units: kg/cm³

distance

measure of particle motion

Units: cm, ft, mile

seven acoustic parameters

period

frequency

amplitude

power

intensity

wavelength

propagation speed

transverse wave

particles move in a perpendicular direction

longitudinal wave

particles move in the same direction as the wave.

in-phase

when two waves peak at the same time and in the same position

out-of-phase

wave peaks occur at different times

intereference

when waves lose their individual characteristics and combine to form a single wave

constructive interference

in-phase waves combine to form a single wave of greater amplitude than either of its components

destructive interference

out-of-phase waves combine into a single wave of lesser amplitude than at least one of its components

when the frequencies of the waves differ:

both constructive and destructive interference occurs