Hertz

The hertz (symbol Hz) is the unit of frequency in the International System of Units (SI) and is defined as one cycle per second. It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves.

One of the unit's most common uses is in the description of sine waves and musical tones, particularly those used in radio and other audio-related applications. It is also used to describe the speeds at which computers and other electronics are driven.

Definition

The hertz is equivalent to cycles per second. In defining the second, the International Committee for Weights and Measures declared that "the standard to be employed is the transition between the hyperfine levels F = 4, M =  0 and F = 3, M = 0 of the ground state 2S_1/2 of the cesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9 192 631 770 hertz" thereby effectively defining the hertz and the second simultaneously.

Hertz (surname)

Hertz is a surname. Notable people with the surname include:

Hertz (crater)

Hertz is a lunar crater that lies on the far side of the Moon, just behind the eastern limb. Due to libration this feature can sometimes be observed from the Earth under favorable lighting conditions. It is located to the west-southwest of the larger crater Fleming, and north-northeast of the smaller Moiseev. Moiseev is joined to Hertz by the satellite crater Moiseev Z, and the three form a short crater chain.

This is a somewhat worn crater formation with a wide inner wall. There is a pear-shaped crater along the northern inner wall. The interior floor is relatively featureless, with only a small ridge offset to the southwest of the midpoint.

Prior to naming in 1961 by the IAU, this crater was known as Crater 200.

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