Physics 18

How much a certain noise will annoy an individual depends on:

-The sound level of the noise -The spectrum of the noise -The person's past experiences -The time of day

In normal conversation you tend to speak at a sound level of about 65 dBA. How much would you need to raise your voice if you were conversing in a third-floor apartment next to a freeway? (See Fig. 18.2 and assume your speech level must be equal to (or just a little higher than) the background sound level that is exceeded 50% of the time. Hint: round the 50% value up to the nearest tens multiple in dBA value [so round to say 50 or 60 or 70 or 80, etc.].)

15 dB

If the average sound level at a dance club is 100 dBA, how long should you be there (assume you don't work there) if you want to protect yourself from hearing loss? (See Table 17.1.)

15 minutes

According to Table 17.1 of maximum exposure times, what is the longest time workers should be exposed to a sound level of 100 dBA per day?

2 hours

According to Figure 18.5, what percentage of the community is likely to be highly annoyed by a day-night noise level of 70 dB?

40%

For a typical urban residential area near a major airport, what outdoor noise level is exceeded 50% of the time? (Use Fig. 18.2.)

60 dB

Which of the following factors could improve speech communication in the presence of noise interference? A. The talker could face the person to whom they are speaking. B. The talker could move closer to the listener. C. The talker could speak with greater effort. D. All of the above.

All of the Above

If noise levels of 55 dBA during the day and 50 dBA at night are allowed as shown in Table 18.2, what is the overall day-night level?

Between 55 ad 60 dB

Suppose a business wants to build a dance club in your city. The business owners claim that the dance club will produce an average noise level of 65 dBA outside the building for several hours at night. Where should the dance club be built to satisfy the typical city noise ordinances found in Table 18.2?

In a heavy industrial area

Because noise is more annoying at night, night levels are adjusted before computing the day-night average level of noise. By approximately how much are the night levels adjusted?

+10 dB