Physics 1 Module 3 & 4 Flashcards
When electric pulses or voltage are applied to certain crystals they will produce sound waves
Reverse piezoelectric
What 4 variables affect sound as it travels through a medium?
- Pressure
- Density
- Particle motion
- Temperature
What can pressure be expressed as?
A sine wave
Regions of low density
Rarefactions
Regions of high density
Compressions
Back and forth particle motion parallel to direction of wave travel
Longitudinal waves
Perpendicular motion to wave travel
Transverse waves
What type of wave is a sound wave?
Longitudinal
Only solids can support which type of waves?
Transverse
When one type of wave is converted to another type of wave
Mode conversion
What’s an example of mode conversion?
Tissue-bone interface
A measurement of how often something happens; the number of complete variations an acoustic variable goes through in one second
Frequency
What is the unit for frequency?
Hertz
The time it takes for one cycle to occur
Period (in microseconds)
The length of space one cycle takes up commonly expressed in millimeters
Wavelength
How does an increase in frequency affect period and wavelength?
Decreased period and wavelength
F=1/T
F=c/wavelength
What is the equation for frequency in relation to period and wavelength?
F=1/T
F=c/wavelength
What is the speed of sound in soft tissue?
1.54 mm/microsecond
1540 m/second
What are the 3 ways to describe the strength of a wave?
Amplitude, intensity, power
Maximum variation of an acoustic variable
Amplitude
Power of wave divided by the area
Intensity
Total energy over the entire cross-sectional area
Power
A small change in amplitude results in what to intensity?
A large change in intensity
How is intensity related to power (p) and area (a)
I=P/a