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 Unit to measure   [  Physics ] (Unit of measure) Dictionary of botanic terminology - index of names

A  unit of measure is a value or magnitude conventionally adopted  in physical measurements. (as of length, surface, volume, time, weight, time,  etc…) , taken as a standard of comparison for others of the same kind

In this web pages we adopted the International System of Units (sometimes referred to as the metric system, symbol: SI) that is is the most widely used system of units  in virtually every country of the world except locally in Liberia, Myanmar and United States, and it is almost globally used in scientific and engineering work.
There are seven  base units and several derived units, together with a set of prefixes plus some Non-SI units accepted for use with SI
Non-SI units can be converted to SI units (or vice versa) according to the conversion of units. Virtually all non-SI units have been redefined in terms of SI units.

 SI Base units of measure The following are the widely accepted fundamental units. Name Symbol Quantity metre m Length kilogram kg Mass second s Time ampere A Electrical Current kelvin K Thermodynamic/Temperature mole mol Amount of substance candela cd Luminous intensity
 SI Derived units with special names Base units can be put together to derive units of measurement for other quantities. Name Symbol Quantity Expressed in base units hertz Hz Frequency s-1 metre newton N Force kg m s -2 joule J Energy N m = kg m2 s-2 watt W Power J/s = kg m2 s-3 pascal Pa Pressure N/m2 = kg m -1 s-2 lumen lm Luminous flux cd lux lx Illuminance cd  m-2 coulomb C Electrical charge A s volt V Electrical potential difference J/C = kg m2 A-1 s-3 ohm Ω Electric resistance V/A = kg m2 A-2 s-3 farad F Electric capacitance Ω-1 s = A2 s4 kg-1 m-2 weber Wb Magnetic flux kg m2 s-2 A-1 tesla T Magnetic flux capacities Wb/m2 = kg s-2 A-1 henry H Indutance Ω s = kg m2 A-2 s-2 siemens S Electric condutance Ω-1 = kg-1 m-2 A2 s3 becquerel Bq Radioactivity (decays per unit time) s-1 gray Gy Absorbed dose (of ionising radiation) J/kg = m2 s-2 sievert Sv Equivalent dose (of ionising radiation) J/kg = m2 s-2 katal kat Catalytic activity mol/s = mol s-1 degree Celtsius °C thermodynamic temperature K - 273.15
 SI prefixes Used to prefix any of the above units to produce a multiple or submultiple of the original unit. 10n Prefix Symbol Short scale Long scale Name Decimal Equivalent 1024 yotta Y Septillion Quadrillion 1 000 000 000 000 000 000 000 000 1021 zetta Z Sextillion Trilliard (thousand trillion) 1 000 000 000 000 000 000 000 1018 exa E Quintillion Trillion 1 000 000 000 000 000 000 1015 peta P Quadrillion Billiard (thousand billion) 1 000 000 000 000 000 1012 tera T Trillion Billion 1 000 000 000 000 109 giga G Billion Milliard (thousand million) 1 000 000 000 106 mega M Million 1 000 000 103 kilo k Thousand 1 000 102 hecto h Hundred 100 101 deca da Ten 10 10−1 deci d Tenth 0.1 10−2 centi c Hundredth 0.01 10−3 milli m Thousandth 0.001 10−6 micro μ Millionth 0.000 001 10−9 nano n Billionth Milliardth 0.000 000 001 10−12 pico p Trillionth Billionth 0.000 000 000 001 10−15 femto f Quadrillionth Billiardth 0.000 000 000 000 001 10−18 atto a Quintillionth Trillionth 0.000 000 000 000 000 001 10−21 zepto z Sextillionth Trilliardth 0.000 000 000 000 000 000 001 10−24 yocto y Septillionth Quadrillionth 0.000 000 000 000 000 000 000 001

 Non-SI units accepted for use with SI Name Symbol Quantity Equivalent SI unit minute min time 1 min = 60 s hour h time 1 h = 60 min = 3600 s day d time 1 d = 24 h = 1440 min = 86400 s degree of arc ° angle 1° = (π/180) rad minute of arc ′ angle 1′ = (1/60)° = (π/10800) rad second of arc ″ angle 1″ = (1/60)′ = (1/3600)° = (π/648000) rad litre l or L volume 0.001 m3 tonne t mass 1 t = 103 kg Empirical non-SI units accepted for use with SI electronvolt eV energy 1eV = 1.60217733 (49) × 10-19 J atomic mass unit u mass 1u = 1.6605402 (10) × 10-27 kg astronomical unit au length 1au = 1.49597870691 (30) × 1011 m Other Non-SI units currently accepted for use with SI nautical mile nautical mile length 1 nautical mile = 1852 m knot knot speed 1 knot = 1 nautical mile per hour = (1852/3600) m/s are a area 1a = 1dam2 = 100 m2 hectare ha area 1ha = 100a = 10000 m2 bar bar pressure 1 bar = 105Pa ångström, angstrom Å length 1 Å = 0.1 nm = 10-10 m barn b area 1b = 10-28 m2

 Common Non-SI units (non accepted for use with SI) Name Symbol Quantity Equivalent SI unit atmosphere atm. pressure 