Problem: Although 0 dB is often referred to as the lower threshold of human hearing, it is important to realize that the human ear is not equally sensitive to all frequencies of sound. In other words, a particular noise may sound louder or softer depending on the frequency of the sound wave being transmitted. Because of this variation, scientists have defined a unit of loudness, called a phon, to represent the intensity of sound waves with a frequency of 1000 Hz: A 60-phon sound is one that is perceived by the human ear to have the same loudness as a sound wave with an intensity of 60 dB and a frequency of 1000 Hz . How many times more intense is the least intense perceptible sound at 100 Hz compared to the least intense perceptible sound at 1000 Hz? Specifically, you are looking for the ratio I100Hz/I1000Hz.

FREE Expert Solution

Intensity:

I=10 log (II0)

I0 = 10-12 W/m2 

At zero phons and 100 Hz, the intensity is 35 dB

At zero phons and 1000 Hz, the intensity is 0 dB

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Problem Details

Although 0 dB is often referred to as the lower threshold of human hearing, it is important to realize that the human ear is not equally sensitive to all frequencies of sound. In other words, a particular noise may sound louder or softer depending on the frequency of the sound wave being transmitted. Because of this variation, scientists have defined a unit of loudness, called a phon, to represent the intensity of sound waves with a frequency of 1000 Hz: A 60-phon sound is one that is perceived by the human ear to have the same loudness as a sound wave with an intensity of 60 dB and a frequency of 1000 Hz .

100 100 phons 80 80 phons 60 60 phons 40 40 phons 20 20 phons O phons 100 1,000 Frequency (in Hz) 5.000 10,000 Intensity (in

 How many times more intense is the least intense perceptible sound at 100 Hz compared to the least intense perceptible sound at 1000 Hz? Specifically, you are looking for the ratio I100Hz/I1000Hz.

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