Sound Properties and Perception

INSTRUCTIONS

1.Which of the following statements are TRUE of sound intensity and decibel levels? Identify all that apply.

1. The intensity of a sound wave has units of Watts/meter.
2. When a sound wave is said to be intense, it means that the particles are vibrating back and forth at a high frequency.
3. Intense sounds are characterized by particles of the medium vibrating back and forth with a relatively large amplitude.
4. Intense sounds are usually perceived as loud sounds.
5. The ability of an observer to hear a sound wave depends solely upon the intensity of the sound wave.
6. From the least intense to the most intense, humans have a rather narrow range of intensity over which sound waves can be heard.
7. The intensity of sound which corresponds to the threshold of pain is one trillion times more intense than the sound which corresponds to the threshold of hearing.
8. Two sounds which have a ratio of decibel ratings equal to 2.0. This means that the second sound is twice as intense as the first sound.
9. Sound A is 20 times more intense than sound B. So if Sound B is rated at 30 dB, then sound A is rated at 50 dB.
10. Sound C is 1000 times more intense than sound D. So if sound D is rated at 80 dB, sound C is rated at 110 dB.
11. A machine produces a sound which is rated at 60 dB. If two of the machines were used at the same time, the decibel rating would be 120 dB.
12. Intensity of a sound at a given location varies directly with the distance from that location to the source of the sound.
13. If the distance from the source of sound is doubled then the intensity of the sound will be quadrupled.
14. If the distance from the source of sound tripled, then the intensity of the sound will be increased by a factor of 6.