Question

Though 0 is often referred to as 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, particular noise can sound louder or softer depending on the frequency of the sound wave being transmitted. since this variation, scientists have defined a unit of loudness, called a phon, to represent the intensity of sound waves with a frequency of 1000: A 60- sound is one that is perceived by the human ear to have the same loudness as a sound wave with an intensity of 60 and a frequency of 1000 .For a sound at 100, what is the decibel level required for human perception?