How is sound intensity measured by the human ear?

Sound intensity in the human ear is measured in decibels (dB), which is a logarithmic unit that quantifies the intensity of sound relative to a reference level. The decibel scale is used because the human ear is capable of hearing a wide range of sound pressures, making it convenient to express these wide variations in a compact scale.

In practical terms, 0 dB represents the threshold of hearing, while higher dB values indicate louder sounds. Importantly, an increase of 10 dB generally corresponds to a tenfold increase in sound intensity, which allows for a more manageable representation of sound levels that we experience in daily life.

Other choices, while related to sound and electricity, do not measure sound intensity. Hertz (Hz) refers to frequency, measuring the number of cycles of sound waves per second; watts quantify power, not sound intensity; and amperes measure electric current. Therefore, decibels are specifically designed to represent sound intensity and are the correct unit utilized by the human ear.