When one person shouts at a football game, the sound intensity level at the cent
ID: 1474940 • Letter: W
Question
When one person shouts at a football game, the sound intensity level at the center of the field is 65.7 dB. When all the people shout together, the intensity level increases to 94.2 dB. Assuming that each person generates the same sound intensity at the center of the field, how many people are at the game? When one person shouts at a football game, the sound intensity level at the center of the field is 65.7 dB. When all the people shout together, the intensity level increases to 94.2 dB. Assuming that each person generates the same sound intensity at the center of the field, how many people are at the game?Explanation / Answer
Start with the definition for sound in dB; it is this: number of dB = 10 log Ir.
So for one person the sound is 10 log Ir = 65.7 dB.
Now for n people the sound is 10 log n*Ir = 10 log n + 10 log Ir = 10 log n + 65.7 = 94.2 dB.
Thus 10 log n = 28.5.
log n = 2.85
n = 10^2.85 = 708
There are about 708 people at the game.