Question

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.

part a
at approximately what frequency do most people perceive the least intense sounds?
enter your answer numerically in hertz to two significant figures.

part b
for a sound at 100 hz, what is the decibel level necessary for human perception?
enter your answer numerically in decibels to two significant figures.

Explanation:

Step1: Analyze human - ear sensitivity graph

The human ear is most sensitive around 3000 Hz. This is the frequency at which most people perceive the least - intense sounds.

Step2: For part B, find value on graph

Looking at the graph, for a frequency of 100 Hz, the decibel level on the 0 - phons (threshold of hearing) curve is approximately 20 dB.

Answer:

Part A: 3000 Hz
Part B: 20 dB