hertz

hertz, unit of frequency. The number of hertz (abbreviated Hz) equals the number of cycles per second.

The units of frequency are called hertz (Hz). Humans with normal hearing can hear sounds between 20 Hz and 20,000 Hz. Frequencies above 20,000 Hz are known as ultrasound. When your dog tilts his head to listen to seemingly imaginary sounds, he is tuning in to ultrasonic frequencies, as high as 45,000 Hz.

The unit hertz is named for Heinrich Rudolf Hertz, a German physicist who lived from 1857 to 1894. He proved the existence of electromagnetic waves - waves of energy including visible light, radio waves, microwaves and more. All of those waves can now be measured in hertz.

Humans can detect sounds in a frequency range from about 20 Hz to 20 kHz. (Human infants can actually hear frequencies slightly higher than 20 kHz, but lose some high-frequency sensitivity as they mature; the upper limit in average adults is often closer to 15–17 kHz.)

The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second.

Heinrich Hertz was a brilliant German physicist and experimentalist who demonstrated that the electromagnetic waves predicted by James Clerk Maxwell actually exist. Hertz is also the man whose peers honored by attaching his name to the unit of frequency; a cycle per second is one hertz.

The "normal" hearing frequency range is between 20 Hz and 20,000 Hz. This range of hearing is influenced by age, occupation and gender. As we age, hearing sensitivity at high frequencies decreases by about 12 kHz. Sounds that are above the threshold of hearing are called ultrasound, those below infrasound.

Generally, the range of human hearing spans 0 decibels (dB) to 120-130 dB. The human hearing range in Hz (hertz) usually includes sounds between 20 Hz and 20,000 Hz (20 kHz). While the upper limit for the average adult is 20,000 Hz, the highest-pitched sounds most people can hear fall between 15,000 to 17,000.

The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second.

The hertz (Hz) is the derived SI unit for frequency. One hertz represents one cycle per second, and thus in base SI units, equates to one per second (1/s). In radiology, it is usually encountered in the context of ultrasound physics.

The hertz is named after the German physicist Heinrich Hertz (1857–1894), who made important scientific contributions to the study of electromagnetism. The name was established by the International Electrotechnical Commission (IEC) in 1935.

Human ears can register sounds from about 20 Hz in frequency up to 20,000 Hz, depending of course, upon the hearer. People with hearing loss usually have trouble hearing sounds in the higher frequency range.