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The SI (metric) system
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SYSTEME INTERNATIONALE D'UNITES (THE INTERNATIONAL SYSTEM OF UNITS)
Table 1.1: Elemental SI units
(quantity) (unit) (formula) (symbol)
length metre -- m
mass kilogram -- kg
time second -- s
electric current ampere -- A
temperature kelvin -- K
luminous intensity candela -- cd
amount of substance mole -- mol
Table 1.2: Supplemental SI units
(quantity) (unit) (formula) (symbol)
plane angle radian -- rad
solid angle steradian -- sr
Table 1.3: Derived SI units
(quantity) (unit) (formula) (symbol)
absorbed dose gray J K^-1 Gy
acceleration m s^-2
activity becquerel s^-1 Bq
area m^2
capacitance farad A s V^-1 F
charge coulomb A s C
density kg m^-3
dose equivalent sievert J K^-1 Sv
electric conductance siemens omega^-1 S
electric field strength V m^-1
energy joule N m J
force newton kg m s^-2 N
frequency hertz s^-1 Hz
illumination lux lm m^-2 lx
inductance henry V s A^-1 H
kinematic viscosity m^2 s^-1
luminance cd m^-2
luminous flux lumen cd sr lm
magnetic field strength A m^-1
magnetic flux weber V s Wb
magnetic flux density tesla Wb m^-2 T
momentum kg m s^-1
power watt J s^-1 W
pressure pascal N m^-2 Pa
resistance ohm V A^-1 omega
stress N m^-2
velocity m s^-1
viscosity N s m^-2
voltage volt W A^-1 V
volume m^3
Table 2: Decimal multiples and submultiples to be used with SI
(prefix) (symbol) (power) (value)
exa E 10^18 1 000 000 000 000 000 000
peta P 10^15 1 000 000 000 000 000
tera T 10^12 1 000 000 000 000
giga G 10^9 1 000 000 000
mega M 10^6 1 000 000
kilo k 10^3 1000
hecto h 10^2 100
deca da 10^1 10
-- -- 10^0 (1) 1
deci d 10^-1 0.1
centi c 10^-2 0.01
milli m 10^-3 0.001
micro (mu) 10^-6 0.000 001
nano n 10^-9 0.000 000 001
pico p 10^-12 0.000 000 000 001
femto f 10^-15 0.000 000 000 000 001
atto a 10^-18 0.000 000 000 000 000 001
Table 3: Conversion of non-SI units to SI units
(from) (to) (multiply by)
(to) (from) (divide by)
inch (in) m 2.54 x 10^-2
feet (ft) m 0.3048
sq. inch (in^2) m^2 6.4516 x 10^-4
sq. foot (ft^2) m^2 9.2903 x 10^-2
cu. inch (in^3) m^3 1.638 71 x 10^-5
cu. foot (ft^3) m^3 2.831 68 x 10^-2
litre (l) m^3 10^-3
gallon (gal) m^3 4.546 09 x 10^-3
mile/hour (mi hr^-1) m s^-1 0.477 04
kilometer/hour (km hr^-1) m s^-1 0.277 78
pound (lb) kg 0.453 592
gram/cm^3 (g cm^-3) kg m^-3 10^3
pound/in^3 kg m^-3 2.767 99 x 10^4
dyne N 10^-5
kgf N 9.806 65
poundal N 0.138 255
lbf N 4.448 22
mmHg Pa 133.322
atmosphere (atm) Pa 1.013 25 x 10^5
horsepower (hp) W 745.7
erg J 10^-7
electronvolt (eV) J 1.602 10 x 10^-19
kilowatt-hour (kW hr) J 3.6 x 10^6
calorie (cal) J 4.1868
Table 4: Fundamental constants
(constant) (symbol) (value)
acceleration of free fall g 9.806 65 m s^-2
Avogadro constant L, N|A 6.022 52 x 10^23 mol^-1
Boltzmann constant k 1.380 622 x 10^-23 J K^-1
electric constant epsilon|0 8.854 x 10^-12 F m^-1
electronic charge e 1.602 192 x 10^-19 C
electronic rest mass m|e 9.109 558 x 10^-31 kg
Faraday constant F 9.648 670 x 10^4 C mol^-1
gas constant R 8.314 34 J K^-1 mol^-1
gravitational constant G 6.664 x 10^-11 N m^2 kg^-2
Loschmidt's constant N|L 2.687 19 x 10^25 m^-3
magnetic cosntant mu|0 4(pi) x 10^-7 H m^-1
neutron rest mass m|n 1.674 92 x 10^-27 kg
Planck constant h 6.626 196 x 10^-34 J s
proton rest mass m|p 1.672 614 x 10^-27 kg
speed of light c 2.997 925 58 x 10^8 m s^-1
Stefan-Boltzmann constant sigma 5.6697 x 10^-8 W m^-2 K^-4
Table 5: Elemental unit definitions
length: metre (m)
The SI unit of length, being the length of the path travelled by
light in vacuum during a time interval of 1/(2.997 924 58 x 10^8)
second.
mass: kilogram (kg)
The SI unit of mass defined as a mass equal to that of the
international platinum-iridium prototype kept by the International
Bureau of Weights and Measures at Sevres, near Paris. (This is the
only base unit still defined by an artifact.)
time: second (s)
The SI unit of time equal to the duration of 9 192 631 770 periods
of the radiation corresponding to the transition between two hyperfine
levels of the ground state of the cesium-133 atom.
electric current: ampere (A)
The SI unit of electric current. The constant current that,
maintained in two straight parallel infinite conductors of negligible
cross section placed one metre apart in vacuum, would produce a force
between the conductors of 2 x 10^-7 N m^-1.
temperature: kelvin (K)
The SI unit of thermodynamic temperature equal to the fraction
1/273.16 of the thermodynamic temperature of the triple point of
water. The magnitude of the kelvin is equal to that of the degree
celsius (centigrade), but a temperature expressed in degrees celsius
is numerically equal to the temperature in kelvins less 273.15. The
former name _degree kevlin_ (symbol degK) became obsolete by
international agreement in 1967.
luminous intensity: candela (cd)
The SI unit of luminous intensity equal to the luminous intensity
in the perpendicular direction of the black-body radiation from an
area of 1/600 000 square metre at the temperature of freezing platinum
(2042 kelvins) under a pressure of 101 325 pascals.
amount of substance: mole (mol)
The SI unit of amount of substance. It is equal to the amount of
substance that contains as many elementary units as there are atoms of
0.012 kg of carbon-12. The elementary units may be atoms, molecules,
ions, radicals, electrons, etc., and must be specified.
Table 6: Standard form (SI) conventions
STANDARD FORM is a way of writing a number, especially a large or
small number, in which only one integer appears before the decimal
point, the value being adjusted by multiplying by the appropriate
power of 10. For example, 236,214 would be written in the standard
form as 2.362 14 x 10^5; likewise, 0.006821047 would be written 6.821
047 x 10^-3. Note that in the standard form, commas are not used, the
digits are grouped into threes, and a space is left between groups.
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