What is the adult upper limit of hearing in Hertz?

The adult upper limit of hearing is commonly accepted to be around 20,000 Hertz (20 kHz). This frequency represents the highest pitch that most adults can hear; however, as people age, the ability to hear higher frequencies typically diminishes due to natural changes in the ear's anatomy and function. Frequencies above 20,000 Hertz are often referred to as ultrasonic and are not perceptible to the human ear.

Understanding this limit is important in various fields, including audio engineering and music production, where certain frequencies may be utilized for different effects and sound design. The choices that indicate frequencies lower than 20,000 Hertz do not represent the typical upper limit of human hearing for adults, making 20,000 Hertz the most accurate answer.