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3 years ago

What is the intensity level of a sound with an intensity of 0.000127 W/m2?

1 answer:

6 0

DB = 10 log (I/Io)
Where, Io is the reference intensity which is the minimum intensity that human can hear.
That is; Io = 10^-12
Therefore;
dB = 10 log (0.000127/10^-12) =80.79
= 81 dB
Therefore; the correct answer is 81 dB

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The question is incomplete. The complete question is :

Two loudspeakers are placed 1.8 m apart. They play tones of equal frequency. If you stand 3.0 m in front of the speakers, and exactly between them, you hear a minimum of intensity. As you walk parallel to the plane of the speakers, staying 3.0 m away, the sound intensity increases until reaching a maximum when you are directly in front of one of the speakers. The speed of sound in the room is 340 m/s.

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Solution :

Given :

The distance between the two loud speakers, $d = 1.8 \ m$

The speaker are in phase and so the path difference is zero constructive interference occurs.

At the point $D$ , the speakers are out of phase and so the path difference is $=\frac{\lambda}{2}$

Therefore,

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Substituting

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