Question

module 1b
threshold of human hearing conceptual question
humans are 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 volatility 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.
there is no simple mathematical formula for converting phons into decibels. the relationship between these two measures of intensity has been determined by experiment. the graph (figure 1) displays the perceived loudness of sound waves of different intensities (vertical axis) and frequencies (horizontal axis). each individual curve represents a sound that is perceived by the human ear to be equivalent to a specific phon - level. to practice reading this graph, note that a sound wave of intensity 70 db that vibrates with a frequency of 50 hz is perceived by the human ear as a 40 - phon sound.
the lowest curve, labeled 0 phons, forms the true lower limit to human sound perception. (actually, even this statement is not completely true owing to variations in sound perception in the general population.)
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part a
at approximately what frequency do most people perceive the least intense sounds?
enter your answer numerically in hertz to two significant figures.

Explanation:

Step1: Analyze the graph

The 0 - phons curve represents the threshold of human hearing. We need to find the frequency on this curve where the intensity is the lowest.

Step2: Locate the minimum - intensity point

Looking at the 0 - phons curve, we can see that the minimum - intensity point occurs around 3000 Hz.

Answer:

3000