Chapter 2 Flashcards
A wave is a
traveling variation in one or more quantities, such as pressure.
All waves carry _ from one location to another
Energy
_ waves: particles move ina direction that is perpendicular to the direction that the wave propagates
Transverse
Longitudinal or transverse wave: light
Transverse
Longitudinal or transverse wave: Sound
Longitudinal
AKA compression waves
Longitudinal
_ waves: particles move in the same direction that the wave propagates
Longitudinal
Sound is a _ wave in which particles in the medium vibrate back and forth from a fixed position
Mechanical
Sound is created by
the vibration of a moving object
Can sound travel in a vacuum
No
When a sound wave travels through a medium, the molecules undergo a series of
Compressions and rarefactions
Areas of increased pressure and density
Compressions
Areas of decreased pressure and density
Rarefactions
Sounds travels in _
A straight line
the effects of the medium upon the sound wave
Acoustic Propagation properties
the effects of the sound wave on the biologic tissue (medium)
Biological effects
A sound wave is AKA
Acoustic wave
_ are used to distinguish between sound waves and other types of waves:
Acoustic variables
3 acoustic variables
Pressure
Density
Distance (particle motion/vibration)
When an acoustic variable changes rhythmically in time, a _ is present
Sound wave
Pressure
concentration of force in an area (force/area)
Density
concentration of mass in a volume
Distance
measure of particle motion
Units for pressure
Pascals (Pa)
Units for density
Kg/cm^3
Units for distance
cm, mm
Sound travels quickest in
Solid
Sound travels slowest in
Gas
_ waves: when the peaks (maximum values) and troughs (minimum values) of the two waves occur at the same time and same location
In-phase
Out of phase waves
the peaks and troughs are at different times and locations, “out of step”
_: when multiple sound beams are traveling in the same medium and arrive at the same location and time, they lose their individual characteristics and combine to form a single wave
Interference
Constructive interference
Takes place with interference of in-phase waves
Results in a single wave of greater amplitude than either of its components
Destructive interference
Results from interference of out-of-phase waves
Resultant wave is smaller than one of its components
When two waves of equal amplitude, _ can occur
Complete destructive interference
