Chapter 3 Flashcards
(22 cards)
The distance sound travels over time
Speed of sound
What is the unit for speed of sound?
c= m/sec or ft/sec
The distance traveled by a single cycle
Wavelength
What is the formula for wavelength?
lambda= speed of sound divided by frequency
What unit is wavelength measured in?
meter/cycle or ft/cycle
The amount of time required to complete one cycle
Period
What is period measured in?
sec/cycle
How do you find period?
T = 1/f
What happens to wavelength as frequency increases?
Decreases
bending of sound waves around the obstacles
Sound diffraction
Occurs when the sound has a shorter wavelength (=high frequency) than the size of the obstacles
Sound shadow
sounds above 1800 Hz (= shorter wavelengths than the human head, 0.6 ft wide / higher frequencies) would be less intense on the other side of the ear
Head shadow effect
Sound is bounced off a smooth, flat surface such as a brick, metal, or wood. The sound bouncing back off creates an echo.
Reflection
sound which is not reflected back. The soft furnishings such as a sofa, carpet or curtains are absorbing the sound.
Absorption
the collection of reflected sounds (echoing sounds) from the surfaces
Reverberation
the length of time required for sound to decay 60 dB from its initial level.
Reverberation time
A change in the sound of an approaching sound source such as train, plane, or ambulance as it passes you; Pitch sounds higher as it gets closer to you
Doppler effect
What happens to the speed of sound as temperature decreases?
Slows down
direction of particle motion is parallel to direction of propagation
Longitudinal wave
direction of particle motion is perpendicular to direction of propagation
Transverse wave
What is an example of a longitudinal wave?
sound waves in air
What is an example of a transverse wave?
a ripple on a pond, stadium wave
