P105 Homework Assignment #6 Complete Solution

Question: #1171

Physics P105: Basic Physics of Sound
Homework Assignment #6:

Make sure you show your work online where relevant for full points.
1. (1 pt) Much of our ability to determine the direction of a sound depends on __ __ hearing, the fact that we have two ears located on opposite sides of our head.
2. (1 pt) Loudness depends on the sound pressure and on the __ of the sound wave.
3. (4 pts) Give the units associated with the following sound parameters: /m2, intensity level: , loudness level: , pitch: . (Spell the units out)
4. (1 pt) The function of the middle ear is to amplify the pressure delivered to the oval window and to protect the inner ear through the . (two words)
5. (2 pt) frequency sounds are localized by their difference in timing between the ears since there is less intensity difference between the ears due to of waves around one's head.
6. (1 pt) That ringing in your ears after sitting through a very loud concert is called .
7. (1 pt) High frequencies excite the basilar membrane close to/far from the oval window.
8. (3 pts) One model of the outer ear canal is a cylindrical pipe 3.0 cm long that is closed at one end by the eardrum. The resonant (fundamental) frequency for this closed pipe is = __ Hz causing a resonance at this frequency in the ear.
9. (1 pt) Sound pressure waves are converted into neural impulses in the spiral .
10. (2 pts) A 4000-Hz tone with a sound intensity level of 30 dB has a loudness level, LL = phons.
11. (4 pts) The sound pressure level of a tone at a loudness level of 30 phons at a frequency of 1000 Hz is dB and dB at a frequency of 125 Hz. (Use the graph on p. 107 of your text.)
12. (3 pts) Hearing sensitivity is a strong function of frequency and reaches a maximum around 3800 Hz. Use the equal-loudness curves on p. 107 to answer the following question about three notes with f1 = 100 Hz, f2 = 1000 Hz, and f3 = 4000 Hz. If all three notes have a sound intensity level of 60 dB, the loudest note is the one with f = Hz (and say why).
13. (3 pts) From the graph of equal loudness contours, the loudness level of the threshold of hearing at 100 Hz is phons and a sound pressure level of dB.
14. (1 pt) Age-related hearing loss is called .