10.4 Intensity of sound [NOT IN CAPS]
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10.4 Intensity of sound [NOT IN CAPS] (ESADE)
Intensity is one indicator of amplitude. Intensity is the energy transmitted over a unit of area each second.
The unit of intensity is the decibel (symbol: dB).
Source |
Intensity (dB) |
Times greater than hearing threshold |
Rocket Launch |
180 |
\(\text{10}^{\text{18}}\) |
Jet Plane |
140 |
\(\text{10}^{\text{14}}\) |
Threshold of Pain |
120 |
\(\text{10}^{\text{12}}\) |
Rock Band |
110 |
\(\text{10}^{\text{11}}\) |
Factory |
80 |
\(\text{10}^{\text{8}}\) |
City Traffic |
70 |
\(\text{10}^{\text{7}}\) |
Normal Conversation |
60 |
\(\text{10}^{\text{6}}\) |
Library |
40 |
\(\text{10}^{\text{4}}\) |
Whisper |
20 |
\(\text{10}^{\text{2}}\) |
Threshold of hearing |
0 |
0 |
Vuvuzelas feature prominently at soccer events in South Africa. The intensity of the sound from a vuvuzela depends on how close you are. In Table 10.4 you can see how the intensity differs.
Frequency (Hz) |
At ear |
Bell opening |
\(\text{1}\) \(\text{m}\) |
\(\text{2}\) \(\text{m}\) |
125 |
36 |
62 |
38 |
35 |
250 |
92 |
106 |
82 |
85 |
500 |
103 |
121 |
102 |
101 |
1 000 |
106 |
122 |
108 |
100 |
2 000 |
101 |
122 |
110 |
101 |
4 000 |
97 |
109 |
110 |
102 |
5 000 |
93 |
111 |
109 |
100 |
8 000 |
87 |
110 |
107 |
98 |
Vuvuzelas in action
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10.5 Ultrasound
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