The Physics
Opus in profectus


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  1. Determine the loudest sound possible (the sound with the greatest pressure level) in decibels…
    1. in the air, on the surface of the Earth
    2. in the ocean, near the equator, 1,000 m below seal level (in the equatorial SOFAR channel)
  2. Normal conversation has an intensity level of around 60 dB. Determine the…
    1. pressure amplitude
    2. density amplitude
    3. displacement amplitude
    4. velocity amplitude
    5. acceleration amplitude
  3. Write something different.
  4. Write something completely different.


  1. Determine the maximum displacement of a gas molecule in the air from a 1,000 Hz tone with an intensity of…
    1. 1 pW/m2 (threshold of sensation)
    2. 1 W/m2 (threshold of pain)
  2. Unlike the threshold of hearing where 20 µPa corresponds to a sound intensity level of 0 dB by definition, there is no standard value for the threshold of pain.
    1. Some sources claim 20 Pa as the threshold of pain.
      1. How many decibels is this?
      2. Determine the corresponding intensity.
    2. Some sources claim 1 W/m2 as the threshold of pain.
      1. Determine the corresponding pressure amplitude.
      2. How many decibels is this?
    Assume room temperature conditions.