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Longitudinal waves show the sinusoidal pattern
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Audible range: 20-20,000 Hz
Ultrasonic and infrasonic
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Sound waves may be graphed several ways |
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Loudness: pressure amplitude
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Pitch: frequency |
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Speed of sound in liquids and solids |
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speed of sound in air |
  the equilibrium gas pressure
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 M the molar mass; R the gas constant
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· Sound will travel in air at roughly 340 m/s. |
· An exact speed would change slightly with humidity, temperature, and nature of the atmosphere.
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Sound intensity |
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Power per unit area:  |
Intensity is the time average of the power per unit area: |
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Since  , we have  |
Sound intensity level  |
 , the reference intensity |
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