Hertz
German physicist who proved electromagnetic waves exist.
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It is an SI derived unit expressed as 1/s or s⁻¹, and its dimension is 1/time (T⁻¹).[1][2] For periodic events, the hertz (Hz) serves as the SI unit of frequency, being equivalent to one occurrence each second.[1][2]
Key facts and history
The hertz replaced the earlier unit name "cycles per second" (cps) and its multiples like "kilocycles per second"[3] The General Conference on Weights and Measures adopted the hertz in 1960.[3] Only frequency uses the unit hertz among quantities with dimension T⁻¹, such as angular velocity or radioactivity.[4] Sound is a traveling longitudinal wave, and humans perceive its frequency as pitch.[5]
The average adult human can hear sounds between 20 and 16000 hertz.[5] In computers, CPU clock rates are expressed in megahertz or gigahertz, referring to the frequency of the master clock signal.[6] The word "hertz" does not change form when used plurally in English.[7] A specific frequency is associated with every musical note.[5]
What the research sources say
The BIPM's 2019 SI Brochure defines the second using the caesium-133 atom's hyperfine transition, establishing that the hyperfine splitting is exactly 9192631770 hertz.[2] The NIST Guide to SI Units notes that "hertz" is spelled the same in plural form.[7] The Unicode Standard includes CJK Compatibility characters for common SI frequency units, intended for compatibility with East Asian encodings.[8] According to a 1967 article by Cartwright, the shift from "cycles per second" to "hertz" in popular media started during the latter part of the 1960s.[9]
References
- Wikipedia, "Hertz" (CC BY-SA 4.0), which cites: "hertz". (1992). American Heritage Dictionary of the English Language (3rd ed.), Boston: Houghton Mifflin.; "SI Brochure: The International System of Units (SI) – 9th edition", BIPM, p. 26 (original not read by us) en.wikipedia.org
- Wikipedia, "Hertz" (CC BY-SA 4.0), which cites: "SI Brochure: The International System of Units (SI) § 2.3.1 Base units", BIPM, 2019, p. 130; "SI Brochure: The International System of Units (SI) § Appendix 1. Decisions of the CGPM and the CIPM", BIPM, 2019, p. 169 (original not read by us) en.wikipedia.org
- Wikipedia, "Hertz" (CC BY-SA 4.0), which cites: "IEC History", Iec.ch (original not read by us) en.wikipedia.org
- Wikipedia, "Hertz" (CC BY-SA 4.0), which cites: "SI brochure, Section 2.2.2, paragraph 6" (original not read by us) en.wikipedia.org
- Wikipedia, "Hertz" (CC BY-SA 4.0), which cites: Ernst Terhardt, "Dominant spectral region", Mmk.e-technik.tu-muenchen.de, 2000-02-20; "Black Hole Sound Waves – Science Mission Directorate", science.nasa.go; "Black Hole Sound Waves – Science Mission Directorate", science.nasa.go (original not read by us) en.wikipedia.org
- Wikipedia, "Hertz" (CC BY-SA 4.0), which cites: Asaravala, "Good Riddance, Gigahertz", 2004-03-30 (original not read by us) en.wikipedia.org
- Wikipedia, "Hertz" (CC BY-SA 4.0), which cites: NIST Guide to SI Units – 9 Rules and Style Conventions for Spelling Unit Names, National Institute of Standards and Technology (original not read by us) en.wikipedia.org
- Wikipedia, "Hertz" (CC BY-SA 4.0), which cites: Unicode Consortium, "The Unicode Standard 12.0 – CJK Compatibility ❰ Range: 3300—33FF ❱", Unicode.org, 2019 (original not read by us) en.wikipedia.org
- Wikipedia, "Hertz" (CC BY-SA 4.0), which cites: Cartwright, "Will Success Spoil Heinrich Hertz?", Fawcett Publications, Inc., March 1967, p. 98–99 (original not read by us) en.wikipedia.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Hertz (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Hertz (CC BY-SA 4.0).
- Word definitions: the , each quoted from its Wikipedia article.
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