Tuesday, October 24, 2006

Testing 1, 2, 3... (Parts 1 - 4)

Okay, I've decided to post the sound test after all. Actually this only covers the first 4 parts and depending how this goes, I may post another one covering later installments. I'm really curious to see how many people are actually reading those articles. The person with the highest score will win a prize. If more than one person has the highest score, I will put their names in a hat and draw a winner. The winner will get to choose between a six-pack of Wisconsin micro-brewed beer or a pound of premium award winning Wisconsin cheese (or maybe I could be convinced to substitute something of equal value). At the end of the test, we have instructions for submitting your answers.

Here's the test:

  1. True or False, sound requires a medium through which to propagate; sound does not travel through a vacuum.
  2. True or false, the speed of sound is faster at lower temperatures.
  3. Airborne sound travels in the form of:
    1. Latitudinal waves
    2. Awesome waves
    3. Transverse waves
    4. Longitudinal waves
    5. Attitudinal waves
  4. In the early evening when the air closer to the ground is still warm and the air higher in the sky is cool, sound waves will:
    1. Bend downward
    2. Continue moving straight
    3. Bend upward
    4. Reflect off the cooler air
  5. True or False, sound waves consist of alternating regions of compression (increased pressure) and rarefaction (decreased pressure). There is also an ambient pressure before the wave propagates.
  6. True or False, a pure tone is a sound with sinusoidal time fluctuations.

  7. The above figure represents a pure tone waveform. True or False, a period (T) is the time it takes for the wave to go from the highest amplitude to the lowest amplitude.
  8. True or false, in general, all sounds move at the same speed within the same medium.
  9. Given a pure tone with a period of 1 ms, what is the frequency of the tone?
  10. If a tree falls in the forest, does it make a sound?
  11. True or false, phase can be used to compare the alignment of two tones of the same frequency. This difference between two tones is known as a phase offset or phase difference. Phase offset is also loosely referred to as simply phase.
  12. Two pure tones with a frequency of 1000 hertz are 90 degrees out of phase. What is their phase offset in units of time?
  13. What is a convenient way to diagram how sound moves?
    1. Bubble diagrams
    2. Wave fronts
    3. Sound rays
    4. Both a and c
    5. Both b and c
  14. Since c (speed of sound) = f (frequency) multiplied times λ (wavelength); what is the wavelength of a pure tone with a frequency of 1500 hertz at STP (standard temperature and pressure)?
  15. True or false, the angles a sound wave hits and reflects off a smooth surface are the same.
  16. When two waves have a non-zero phase offset, they are said to be in phase. When two waves have zero phase offset, they are out of phase.
  17. True or false, when a sound wave refracts through another material with a higher speed of sound, the wavelength of the sound wave will decrease.
  18. True or false, the frequency (f) is the rate at which the wave repeats (cycles per second, called hertz).

To qualify for entry into this "contest", you must leave a comment to this post with some way to identify yourself -- maybe leave a nickname and your location. DO NOT INCLUDE YOUR ANSWERS IN YOUR COMMENT. Then submit your answers to soundtest1@amplioaudio.com. Be sure to include the same nickname identified in the exam's comments. The winner will be announced next Tuesday (Halloween), so you can submit answers until Monday night, which is October 30th.

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