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Statmho
The statmho is the unit of electrical conductance in the electrostatic system of units (ESU), an extension of the centimeter-gram-second (CGS) system to cover electrical units. It is sometimes called the statsiemens, with symbol statS. Conversion In the ESU system, the permittivity of free space is set to unity by definition. This results in unit conversions to the SI system containing a power of the speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit ..., ''c'', as well as a power of 10. In the case of the statmho, the conversion from siemens (S) is given by:Donald Fenna, ''A Dictionary of Weights, Measures, and Units'', pp. 83–84, Oxford University Press, 2002 . :1 S ≘ ''c''2 × 10−5 s2/m2 × 1 statmho. The value of ''c'' in the SI system is metres p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Conductance
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with mechanical friction. The SI unit of electrical resistance is the ohm (), while electrical conductance is measured in siemens (S) (formerly called the 'mho' and then represented by ). The resistance of an object depends in large part on the material it is made of. Objects made of electrical insulators like rubber tend to have very high resistance and low conductance, while objects made of electrical conductors like metals tend to have very low resistance and high conductance. This relationship is quantified by resistivity or conductivity. The nature of a material is not the only factor in resistance and conductance, however; it also depends on the size and shape of an object because these properties are extensive rather than inten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrostatic Units
The electrostatic system of units (CGS-ESU) is a system of units used to measure quantities of electric charge, electric current, and voltage within the centimetre–gram–second (or "CGS") system of metric units. In electrostatic units, electrical charge is defined by the force that it exerts on other charges. Although CGS units have mostly been replaced by the '' International System of Units'', electrostatic units are still in occasional use in some applications, most notably in certain types of physics such as in particle physics and astrophysics. The main electrostatic units are: *The statcoulomb, called the franklin or the "esu" for electric charge *The statvolt for voltage *The statampere for electric current. The CGS-ESU units for magnetic quantities are seldom used, and don't have special names. Sources tend to just use 'esu' or the derived unit expressed in terms of the CGS base units. For example, the unit for magnetic induction is g/cm, corresponding to ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permittivity Of Free Space
Vacuum permittivity, commonly denoted (pronounced "epsilon nought" or "epsilon zero"), is the value of the absolute dielectric permittivity of classical vacuum. It may also be referred to as the permittivity of free space, the electric constant, or the distributed capacitance of the vacuum. It is an ideal (baseline) physical constant. Its CODATA value is: : (farads per meter), with a relative uncertainty of It is a measure of how dense of an electric field is "permitted" to form in response to electric charges, and relates the units for electric charge to mechanical quantities such as length and force. For example, the force between two separated electric charges with spherical symmetry (in the vacuum of classical electromagnetism) is given by Coulomb's law: :F_\text = \frac \frac Here, ''q''1 and ''q''2 are the charges, ''r'' is the distance between their centres, and the value of the constant fraction 1/4 \pi \varepsilon_0 (known as the Coulomb constant, ''k''e) is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Of Light
The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit for the speed at which conventional matter or energy (and thus any signal carrying information) can travel through space. All forms of electromagnetic radiation, including visible light, travel at the speed of light. For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and very sensitive measurements, their finite speed has noticeable effects. Starlight viewed on Earth left the stars many years ago, allowing humans to study the history of the universe by viewing distant objects. When communicating with distant space probes, it can take minutes to hours for signals to travel from Earth to the spacecraft and vice versa. In computing, the speed of light fixes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siemens (unit)
The siemens (symbol: S) is the unit of electric conductance, electric susceptance, and electric admittance in the International System of Units (SI). Conductance, susceptance, and admittance are the reciprocals of resistance, reactance, and impedance respectively; hence one siemens is redundantly equal to the reciprocal of one ohm () and is also referred to as the '' mho''. The 14th General Conference on Weights and Measures approved the addition of the siemens as a derived unit in 1971. The unit is named after Ernst Werner von Siemens. In English, the same word ''siemens'' is used both for the singular and plural. Like other SI units named after people, the symbol is capitalized but the name of the unit is not. For the siemens this is particularly important to distinguish it from the second, symbol (lower case) s. The related property, electrical conductivity, is measured in units of siemens per metre (S/m). Definition For an element conducting direct current, electrica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centimetre–gram–second System Of Units
The centimetre–gram–second system of units (abbreviated CGS or cgs) is a variant of the metric system based on the centimetre as the unit of length, the gram as the unit of mass, and the second as the unit of time. All CGS mechanical units are unambiguously derived from these three base units, but there are several different ways in which the CGS system was extended to cover electromagnetism. The CGS system has been largely supplanted by the MKS system based on the metre, kilogram, and second, which was in turn extended and replaced by the International System of Units (SI). In many fields of science and engineering, SI is the only system of units in use, but there remain certain subfields where CGS is prevalent. In measurements of purely mechanical systems (involving units of length, mass, force, energy, pressure, and so on), the differences between CGS and SI are straightforward and rather trivial; the unit-conversion factors are all powers of 10 as and . For example, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
