SI derived units are part of the SI system of measurement units and are derived from the seven SI base units. The International System of Units (SI defines seven dimensionally independent SI base units.
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Derived units with special names
Base units can be put together to derive units of measurement for other quantities. In addition to the two dimensionless derived units radian (rad) and steradian (sr) there are 20 derived units having special names:
| Name | Symbol | Quantity | Expression in terms of other units | Expression in terms of SI base units |
|---|---|---|---|---|
| hertz | Hz | frequency | 1/s | s−1 |
| newton | N | force, weight | m∙kg/s2 | m∙kg∙s−2 |
| pascal | Pa | pressure, stress | N/m2 | m−1∙kg∙s−2 |
| joule | J | energy, work, heat | N∙m = C·V = W·s | m2∙kg∙s−2 |
| watt | W | power, radiant flux | J/s = V·A | m2∙kg∙s−3 |
| coulomb | C | electric charge or electric flux | s∙A | s∙A |
| volt | V | voltage, electrical potential difference, electromotive force | W/A = J/C | m2∙kg∙s−3∙A−1 |
| farad | F | electric capacitance | C/V | m−2∙kg−1∙s4∙A2 |
| ohm | Ω | electric resistance, impedance, reactance | V/A | m2∙kg∙s−3∙A−2 |
| siemens | S | electrical conductance | 1/Ω | m−2∙kg−1∙s3∙A2 |
| weber | Wb | magnetic flux | J/A | m2∙kg∙s−2∙A−1 |
| tesla | T | magnetic field | V∙s/m2 = Wb/m2 = N/(A∙m) | kg∙s−2∙A−1 |
| henry | H | inductance | V∙s/A = Wb/A | m2∙kg∙s−2∙A−2 |
| Celsius | °C | Celsius Temperature | t°C = tK − 273. The radian is a unit of plane Angle, equal to 180/ π degrees, or about 57 The steradian (symbol sr) is the SI unit of Solid angle. It is used to describe two-dimensional angular spans in three- Dimensional space The musical instrument is spelled Cymbal. A symbol is something --- such as an object, Picture, written word a sound a piece A physical Quantity is a physical property that can be quantified The International System of Units (SI defines seven dimensionally independent SI base units. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. Frequency is a measure of the number of occurrences of a repeating event per unit Time. The newton (symbol N) is the SI derived unit of Force, named after Isaac Newton in recognition of his work on Classical In Physics, a force is whatever can cause an object with Mass to Accelerate. In the Physical sciences weight is a Measurement of the gravitational Force acting on an object Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface Stress is a measure of the average amount of Force exerted per unit Area. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός In Physics, mechanical work is the amount of Energy transferred by a Force. In Physics, heat, symbolized by Q, is Energy transferred from one body or system to another due to a difference in Temperature The watt (symbol W) is the SI derived unit of power, equal to one Joule of energy per Second. In Physics, power (symbol P) is the rate at which work is performed or energy is transmitted or the amount of energy required or expended for In Radiometry, radiant flux or radiant power is the measure of the total power of Electromagnetic radiation (including Infrared, The coulomb (symbol C) is the SI unit of Electric charge. It is named after Charles-Augustin de Coulomb. Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. In the various subfields of Physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks The volt (symbol V) is the SI derived unit of electric Potential difference or Electromotive force. Electrical tension (or voltage after its SI unit, the Volt) is the difference of electrical potential between two points of an electrical In Physics, the potential difference or pd between two points is the difference of the points' Scalar potential, equivalent to the line integral Electromotive force ( emf, \mathcal{E} is a term used to characterize electrical devices such as Voltaic cells thermoelectric devices electrical This is about the capacitance unit of measure For the charge unit see Faraday (unit. Capacitance is a measure of the amount of Electric charge stored (or separated for a given Electric potential. The ohm (symbol Ω) is the SI unit of Electrical impedance or in the Direct current case Electrical resistance, Electrical resistance is a ratio of the degree to which an object opposes an Electric current through it measured in Ohms Its reciprocal quantity is Electrical impedance, or simply impedance, describes a measure of opposition to a sinusoidal Alternating current (AC The siemens (symbol S is the SI derived unit of Electric conductance. Electrical conductance is a measure of how easily Electricity flows along a certain path through an Electrical element. In Physics, the weber (symbol Wb ˈveɪbɚ ˈwiːbɚ is the SI unit of Magnetic flux. Magnetic flux, represented by the Greek letter Φ ( Phi) is a measure of quantity of Magnetism, taking into account the strength and the extent of a Magnetic The tesla (symbol T) is the SI derived unit of Magnetic field B (which is also known as "magnetic flux density" and "magnetic In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges The henry (symbol H is the SI unit of Inductance. It is named after Joseph Henry (1797-1878 the American scientist who discovered electromagnetic In Electrical circuits, any Electric current i produces a Magnetic field and hence generates a total Magnetic flux \Phi acting The Celsius Temperature scale was previously known as the centigrade scale. The Celsius Temperature scale was previously known as the centigrade scale. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature 15 | K |
| lumen | lm | luminous flux | cd∙sr | cd |
| lux | lx | illuminance | lm/m2 | m−2∙cd |
| becquerel | Bq | radioactivity (decays per unit time) | 1/s | s−1 |
| gray | Gy | absorbed dose (of ionizing radiation) | J/kg | m2∙s−2 |
| sievert | Sv | equivalent dose (of ionizing radiation) | J/kg | m2∙s−2 |
| katal | kat | catalytic activity | mol/s | s−1∙mol |
Other quantities and units
| Compound units derived from SI units | ||||
|---|---|---|---|---|
| Name | Symbol | Quantity | Expression in terms of SI base units |
|
| square metre | m2 | area | m2 | |
| cubic metre | m3 | volume | m3 | |
| metre per second | m/s | speed, velocity | m·s−1 | |
| metre per second squared | m/s2 | acceleration | m·s−2 | |
| metre per second cubed | m/s3 | jerk | m·s−3 | |
| metre per second4 | m/s4 | snap | m·s−4 | |
| radian per second | rad/s | angular velocity | s−1 | |
| newton second | N·s | momentum, impulse | kg·m·s−1 | |
| newton metre second | N·m·s | angular momentum | kg·m2·s−1 | |
| newton metre | N·m | torque, moment of force | kg·m2·s−2 | |
| reciprocal metre | m−1 | wavenumber | m−1 | |
| kilogram per cubic metre | kg/m3 | density, mass density | kg·m−3 | |
| cubic metre per kilogram | m3/kg | specific volume | kg−1·m3 | |
| mole per cubic metre | mol/m3 | amount (-of-substance) concentration | m−3·mol | |
| cubic metre per mole | m3/mol | molar volume | m3·mol−1 | |
| joule per kelvin | J/K | heat capacity, entropy | kg·m2·s−2·K−1 | |
| joule per kelvin mole | J/(K·mol) | molar heat capacity, molar entropy | kg·m2·s−2·K−1·mol−1 | |
| joule per kilogram kelvin | J/(K·kg) | specific heat capacity, specific entropy | m2·s−2·K−1 | |
| joule per mole | J/mol | molar energy | kg·m2·s−2·mol−1 | |
| joule per kilogram | J/kg | specific energy | m2·s−2 | |
| joule per cubic metre | J/m3 | energy density | kg·m−1·s−2 | |
| newton per metre | N/m = J/m2 | surface tension | kg·s−2 | |
| watt per square metre | W/m2 | heat flux density, irradiance | kg·s−3 | |
| watt per metre kelvin | W/(m·K) | thermal conductivity | kg·m·s−3·K−1 | |
| square metre per second | m2/s | kinematic viscosity, diffusion coefficient | m2·s−1 | |
| pascal second | Pa·s = N·s/m2 | dynamic viscosity | kg·m−1·s−1 | |
| coulomb per cubic metre | C/m3 | electric charge density | m−3·s·A | |
| ampere per square metre | A/m2 | electric current density | A·m−2 | |
| siemens per metre | S/m | conductivity | kg−1·m−3·s3·A2 | |
| siemens square metre per mole | S·m2/mol | molar conductivity | kg-1·s3·mol−1·A2 | |
| farad per metre | F/m | permittivity | kg−1·m−3·s4·A2 | |
| henry per metre | H/m | permeability | kg·m·s−2·A−2 | |
| volt per metre | V/m | electric field strength | kg·m·s−3·A−1 | |
| ampere per metre | A/m | magnetic field strength | A·m−1 | |
| candela per square metre | cd/m2 | luminance | cd·m−2 | |
| coulomb per kilogram | C/kg | exposure (X and gamma rays) | kg−1·s·A | |
| gray per second | Gy/s | absorbed dose rate | m2·s−3 | |
| ohm metre | Ω·m | resistivity | kg·m3·s−3·A−2 | |
See also
References
- I. The lumen (symbol lm) is the SI unit of Luminous flux, a measure of the perceived power of Light. In photometry, luminous flux or luminous power is the measure of the perceived power of Light. LUX is the principal centre for the promotion and distribution of experimental Film and Video works in the UK. In photometry, illuminance is the total Luminous flux incident on a surface per unit Area. The becquerel (symbol Bq) is the SI derived unit of radioactivity. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The gray (symbol Gy is the SI unit of absorbed radiation dose. Absorbed dose (also known as total ionizing dose, TID is a measure of the energy deposited in a medium by Ionizing radiation. Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation The sievert (symbol Sv is the SI derived unit of dose equivalent. The equivalent dose ( H T) is a measure of the Radiation dose to tissue where an attempt has been made to allow for the different relative biological The katal (symbol kat is the SI unit of catalytic activity It is a derived SI unit for expressing quantity values of catalytic activity of Enzymes Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst M^2 redirects here For other uses see M². CM2 redirects here Area is a Quantity expressing the two- Dimensional size of a defined part of a Surface, typically a region bounded by a closed Curve. CM3 redirects here If you were looking for the 3rd game in the Cooking Mama series abbreviated as CM3 see here. The volume of any solid plasma vacuum or theoretical object is how much three- Dimensional space it occupies often quantified numerically Speed is the rate of motion, or equivalently the rate of change in position often expressed as Distance d traveled per unit of In Physics, velocity is defined as the rate of change of Position. In Physics, jerk, jolt (especially in British English) surge or lurch, is the rate of change of Acceleration; that is Do not confuse with Angular frequency The unit for angular velocity is rad/s Newton-second (symbol Ns, N s or N·s) is the derived SI unit of Impulse and Momentum. In Classical mechanics, momentum ( pl momenta SI unit kg · m/s, or equivalently N · s) is the product In Classical mechanics, an impulse is defined as the Integral of a Force with respect to Time: \mathbf{I} = \int \mathbf{F}\ In Physics, the angular momentum of a particle about an origin is a vector quantity equal to the mass of the particle multiplied by the Cross product of the position A torque (τ in Physics, also called a moment (of force is a pseudo- vector that measures the tendency of a force to rotate an object about Wavenumber in most physical sciences is a Wave property inversely related to Wavelength, having SI units of reciprocal meters Kilogram per cubic metre is the SI measure of Density and is represented as kg/m³ where kg stands for Kilogram and m³ stands for Cubic metre The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Specific volume (v is the volume occupied by a unit of mass of a material Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity In Thermodynamics (a branch of Physics) entropy, symbolized by S, is a measure of the unavailability of a system ’s Energy Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity For the work of fiction see Surface Tension (short story. Surface tension is a property of the surface of a Liquid that causes it to In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. Metres squared per second is the SI derived unit of Angular momentum, defined by Distance or displacement in Metres multiplied by distance Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. Electrical conductivity or specific conductivity is a measure of a material's ability to conduct an Electric current. Permittivity is a Physical quantity that describes how an Electric field affects and is affected by a Dielectric medium and is determined by the ability In Electromagnetism, permeability is the degree of Magnetization of a material that responds linearly to an applied Magnetic field. In Physics, the space surrounding an Electric charge or in the presence of a time-varying Magnetic field has a property called an electric field (that can In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges Luminance is a photometric measure of the density of Luminous intensity in a given direction The International System of Units (SI defines seven dimensionally independent SI base units. An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol to form a Decimal multiple or Planck units are Units of measurement named after the German physicist Max Planck, who first proposed them in 1899 Mills, Tomislav Cvitas, Klaus Homann, Nikola Kallay, IUPAC: Quantities, Units and Symbols in Physical Chemistry, 2nd edition (June 1993), Blackwell Science Inc (p. 72)
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