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Meter (unit)
The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of of a second, where the second is defined by a hyperfine transition frequency of caesium. The metre was originally defined in 1791 by the French National Assembly as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's polar circumference is approximately . In 1799, the metre was redefined in terms of a prototype metre bar. The bar used was changed in 1889, and in 1960 the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the path trav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length
Length is a measure of distance. In the International System of Quantities, length is a quantity with Dimension (physical quantity), dimension distance. In most systems of measurement a Base unit (measurement), base unit for length is chosen, from which all other units are derived. In the International System of Units (SI) system, the base unit for length is the metre. Length is commonly understood to mean the most extended size, dimension of a fixed object. However, this is not always the case and may depend on the position the object is in. Various terms for the length of a fixed object are used, and these include height, which is vertical length or vertical extent, width, breadth, and depth. ''Height'' is used when there is a base from which vertical measurements can be taken. ''Width'' and ''breadth'' usually refer to a shorter dimension than ''length''. ''Depth'' is used for the measure of a third dimension. Length is the measure of one spatial dimension, whereas area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Circle
In mathematics, a great circle or orthodrome is the circular intersection of a sphere and a plane passing through the sphere's center point. Discussion Any arc of a great circle is a geodesic of the sphere, so that great circles in spherical geometry are the natural analog of straight lines in Euclidean space. For any pair of distinct non- antipodal points on the sphere, there is a unique great circle passing through both. (Every great circle through any point also passes through its antipodal point, so there are infinitely many great circles through two antipodal points.) The shorter of the two great-circle arcs between two distinct points on the sphere is called the ''minor arc'', and is the shortest surface-path between them. Its arc length is the great-circle distance between the points (the intrinsic distance on a sphere), and is proportional to the measure of the central angle formed by the two points and the center of the sphere. A great circle is the largest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric System
The metric system is a system of measurement that standardization, standardizes a set of base units and a nomenclature for describing relatively large and small quantities via decimal-based multiplicative unit prefixes. Though the rules governing the metric system have changed over time, the modern definition, the International System of Units (SI), defines the metric prefixes and seven base units: metre (m), kilogram (kg), second (s), ampere (A), kelvin (K), Mole (unit), mole (mol), and candela (cd). An SI derived unit is a named combination of base units such as hertz (cycles per second), Newton (unit), newton (kg⋅m/s2), and tesla (unit), tesla (1 kg⋅s−2⋅A−1) and in the case of Celsius a shifted scale from Kelvin. Certain units have been Non-SI units mentioned in the SI#Units officially accepted for use with the SI, officially accepted for use with the SI. Some of these are decimalised, like the litre and electronvolt, and are considered "metric". Others, like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philippine English
Philippine English is a variety of English native to the Philippines, including those used by the media and the vast majority of educated Filipinos and English learners in the Philippines from adjacent Asian countries. English is taught in schools as one of the two official languages of the country, the other being Filipino, a standardized form of Tagalog. Due to the influx of Philippine English teachers overseas, Philippine English is also becoming the prevalent variety of English being learned in the Far East as taught by Filipino teachers in various Asian countries such as South Korea, Japan, and Thailand among others. Due to the highly multilingual and bilingual nature of the Philippines, code-switching such as Taglish ( Tagalog-infused English) and Bislish (English infused with any of the Bisayan languages) is prevalent across domains from casual settings to formal situations. Philippine English is similar and related to American English but in nativized form. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taylor2008b
Taylor, Taylors or Taylor's may refer to: People * Taylor (surname) ** List of people with surname Taylor * Taylor (given name), including Tayla and Taylah * Taylor sept, a branch of Scottish clan Cameron * Justice Taylor (other) Places Australia * Electoral district of Taylor, South Australia * Taylor, Australian Capital Territory, planned suburb Canada * Taylor, British Columbia United States * Taylor, Alabama * Taylor, Arizona * Taylor, Arkansas * Taylor, Indiana * Taylor, Louisiana * Taylor, Maryland * Taylor, Michigan * Taylor, Mississippi * Taylor, Missouri * Taylor, Nebraska * Taylor, North Dakota * Taylor, New York * Taylor, Beckham County, Oklahoma * Taylor, Cotton County, Oklahoma * Taylor, Pennsylvania * Taylors, South Carolina * Taylor, Texas * Taylor, Utah * Taylor, Washington * Taylor, West Virginia * Taylor, Wisconsin * Taylor, Wyoming * Taylor County (other) * Taylor Township (other) Businesses and organisation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turner
Turner may refer to: People and fictional characters * Turner (surname), a common surname, including a list of people and fictional characters with the name * Turner (given name), a list of people with the given name *One who uses a lathe for turning Places Australia * Turner, Australian Capital Territory * Turner River, Western Australia Canada * Turner, Ontario United States * Turner, Mississippi County, Arkansas * Turner, Phillips County, Arkansas *Turner, former name of Tuttle, California * Turner, Indiana *Turner, Kansas * Turner, Maine, a New England town ** Turner (CDP), Maine, within the town of Turner * Turner, Michigan * Turner, Montana * Turner, Oregon * Turner, Washington * Turner, West Virginia * Turner Air Force Base, outside Albany, Georgia * Turner County, Georgia * Turner County, South Dakota Businesses * Turner Broadcasting System, part of WarnerMedia, managed a collection of cable networks and properties **TBS (American TV channel), a channel owned by Turner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Bureau Of Weights And Measures
The International Bureau of Weights and Measures (, BIPM) is an List of intergovernmental organizations, intergovernmental organisation, through which its 64 member-states act on measurement standards in areas including chemistry, ionising radiation, physical metrology, as well as the International System of Units (SI) and Coordinated Universal Time (UTC). It is headquartered in the Pavillon de Breteuil in Saint-Cloud, near Paris, France. The organisation has been referred to as IBWM (from its name in English) in older literature. Function The BIPM has the mandate to provide the basis for a single, coherent system of measurements throughout the world, traceable to the International System of Units, International System of Units (SI). This task takes many forms, from direct dissemination of units to coordination through international comparisons of national measurement standards (as in electricity and ionising radiation). Following consultation, a draft version of the BIPM Work ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parts Per Million
In science and engineering, the parts-per notation is a set of pseudo-units to describe the small values of miscellaneous dimensionless quantity, dimensionless quantities, e.g. mole fraction or mass fraction (chemistry), mass fraction. Since these fraction (mathematics), fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement. Commonly used are * parts-per-million - ppm, * parts-per-billion - ppb, * parts-per-trillion - ppt, * parts-per-quadrillion - ppq, This notation is not part of the International System of Units - SI system and its meaning is ambiguous. Applications Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water. The quantity "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution. When working with aqueous solutions, it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2019 Revision Of The SI
In 2019, four of the seven SI base units specified in the International System of Quantities were redefined in terms of natural physical constants, rather than human artefacts such as the standard kilogram. Effective 20 May 2019, the 144th anniversary of the Metre Convention, the kilogram, ampere, kelvin, and mole are defined by setting exact numerical values, when expressed in SI units, for the Planck constant ('), the elementary electric charge ('), the Boltzmann constant (), and the Avogadro constant (), respectively. The second, metre, and candela had previously been redefined using physical constants. The four new definitions aimed to improve the SI without changing the value of any units, ensuring continuity with existing measurements. In November 2018, the 26th General Conference on Weights and Measures (CGPM) unanimously approved these changes, The conference ran from 13–16 November and the vote on the redefinition was scheduled for the last day. Kazakhstan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light
Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequency, frequencies of 750–420 terahertz (unit), terahertz. The visible band sits adjacent to the infrared (with longer wavelengths and lower frequencies) and the ultraviolet (with shorter wavelengths and higher frequencies), called collectively ''optical radiation''. In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity (physics), intensity, propagation direction, frequency or wavelength spectrum, and polarization (waves), polarization. Its speed of light, speed in vacuum, , is one of the fundamental physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
