PhysicsLAB Review
Sound

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Resource Lessons
 
 
Labs
 
 
Worksheets
 
EPD
 
Textbook Assignments
 
 
NextTime Questions
 
 
Vocabulary
 
wave vw = fλ
mechanical non-mechanical
longitudinal radio waves vs sound waves
damped heat
compression rarefaction
amplitude (pressure/density) point source
frequency (f) hertz
kilohertz megahertz
vibration period (T)
equilibrium position wavelength (λ)
relationship between frequency and wavelength
relationship between frequency and period
human range of frequencies infrasonic
ultrasonic intensity, decibels
interference beats
beat pitch beat frequency
constructive destructive
EPD in-phase, coherent sources
antinodes (A) nodes (N)
loops resonance
forced vibration natural frequency
properties of open pipes properties of closed pipes
harmonics overtones
standing waveform for an open water column
reflection
echo reverberation
speed of sound (dry air)
speed of sound increases with the medium's
rigidity, temperature, humidity
 
 
Formulas
 
vw = fλ d = rt
sound level dB to power
   take the difference in the decibels, divide that difference by 10,
   relationship between the original sound levels equals 10x power
intensity of sound (watts/m2)
comparison of two intensity values
sound level intensity (dB)
   threshold of human hearing (Io = 1 x 10-12 watts/m2)
beats beat frequency = |f2 - f1|
beat pitch = ½(f1 + f2)
speed of sound in dry air vw = 331 + 0.6T
open-closed pipe for the fundamental, A-N
   Lpipe = ½ loop = ¼λ
open-open pipe for the fundamental, A-N-A
   Lpipe = 1 loop = ½λ
EPD = |L1 - L2} constructive: mλ
   m ∈ {0, 1, 2, 3, ....} remember L1 can equal L2
destructive: ½(2m - 1)λ
   m ∈ {1, 2, 3, ....}
listener moving Δf / f = v / vw
   approaching: f' = f + Δf
   receding: f' = f - Δf
source moving Δλ/λ = v / vw
   approaching: λ' = λ - Δλ
   receding: λ' = λ + Δλ
 



 
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