194 lines
4.1 KiB
Groff
194 lines
4.1 KiB
Groff
.Dd $Mdocdate: April 2 2022 $
|
|
.Dt SI 7
|
|
.Os
|
|
.Sh NAME
|
|
.Nm SI
|
|
.Nd The International System of Units
|
|
.Sh SOURCE
|
|
NIST SP 330,
|
|
.Em The International System of Units (SI) ,
|
|
2019 edition,
|
|
.Lk https://doi.org/10.6028/NIST.SP.330-2019 .
|
|
Some data from the
|
|
.Sx NOT-ACCEPTABLE NON-SI UNITS STILL IN USE
|
|
section are from NIST SP 811,
|
|
.Em NIST Guide for the Use of the International System of Units (SI) ,
|
|
2008,
|
|
.Lk https://www.nist.gov/pml/special-publication-811 .
|
|
.Sh PREFIXES
|
|
.TS
|
|
allbox tab( );
|
|
c | c | c || c | c | c
|
|
l c r || l c r.
|
|
Name Prefix Power Name Prefix Power
|
|
yotta Y 24 yocto y -24
|
|
zetta Z 21 zepto z -21
|
|
exa E 18 atto a -18
|
|
peta P 15 femto f -15
|
|
tera T 12 pico p -12
|
|
giga G 9 nano n -9
|
|
mega M 6 micro \(mc -6
|
|
kilo k 3 milli m -3
|
|
hecto h 2 centi c -2
|
|
deka da 1 deci d -1
|
|
.TE
|
|
.Sh BASE UNITS
|
|
.TS
|
|
allbox;
|
|
r | l | c | c
|
|
r l c c.
|
|
Quantity Unit Symbol Dimension
|
|
time second s T
|
|
length meter m L
|
|
kilogram mass m M
|
|
current ampere A I
|
|
temperature kelvin K \(*H
|
|
luminosity candela cd J
|
|
Unitless = 1 =
|
|
.TE
|
|
Unitless quantities (like indices of refraction) are usually written
|
|
with no symbol at all, or with a conventional symbol, like
|
|
.Dq rad
|
|
(see below).
|
|
.Sh DERIVED UNITS
|
|
.TS
|
|
allbox;
|
|
r | l | c | c | c
|
|
l l c c c.
|
|
Quantity Unit Symbol Base Units Equivalent
|
|
plane angle radian rad m/m 1
|
|
solid angle steradian sr m\(S2/m\(S2 1
|
|
frequency hertz Hz s⁻¹ =
|
|
force newton N kg m s⁻² =
|
|
T{
|
|
pressure, stress
|
|
T} pascal Pa kg m⁻¹ s⁻² N m⁻²
|
|
T{
|
|
energy, work, heat
|
|
T} joule J kg m² s⁻² N m
|
|
T{
|
|
power, radiant flux
|
|
T} watt W kg m² s⁻³ J/s
|
|
T{
|
|
electric potential difference
|
|
T} volt V kg m² s⁻³ A⁻¹ W/A
|
|
charge columb C A s =
|
|
capacitance farad F kg⁻¹ m⁻² s⁴ A² C/V
|
|
resistance ohm \(*W kg m² s⁻³ A⁻² V/A
|
|
conductance siemens S kg⁻¹ m⁻² s³ A² A/V
|
|
T{
|
|
magnetic flux
|
|
T} weber Wb kg m² s⁻² A⁻¹ V s
|
|
T{
|
|
magnetic flux density
|
|
T} tesla T kg s⁻² A⁻¹ Wb m⁻²
|
|
inductance henry H kg m² s⁻² A⁻² Wb/A
|
|
T{
|
|
temperature, celsius
|
|
T} celsius \(de C K + 273.15 =
|
|
T{
|
|
luminous flux
|
|
T} lumen lm cd sr =
|
|
T{
|
|
illuminance
|
|
T} lux cd sr m⁻² lm m⁻²
|
|
T{
|
|
activity referred to a
|
|
radionuclide
|
|
T} becquerel Bq s⁻¹ =
|
|
T{
|
|
absorbed dose, kerma
|
|
T} gray m² s⁻² J/kg
|
|
T{
|
|
dose equivalent
|
|
T} sievert Sv m² s⁻² J/kg
|
|
T{
|
|
catalytic activity
|
|
T} katal kat mol s⁻¹ =
|
|
.TE
|
|
The equivalent units for pressure do not appear in the source.
|
|
.Sh SAMPLE OF OTHER DERIVED UNITS
|
|
.TS
|
|
allbox;
|
|
l r r.
|
|
Quantity Units Base
|
|
dynamic viscosity Pa s kg m⁻¹ s⁻¹
|
|
surface tension N m kg m² s⁻²
|
|
T{
|
|
angular velocity, angular frequency
|
|
T} rad s⁻¹ s⁻¹
|
|
T{
|
|
heat flux density, irradiance
|
|
T} W m⁻² kg s⁻³
|
|
T{
|
|
heat capacity, entropy
|
|
T} J K⁻¹ kg m² s⁻² K⁻¹
|
|
T{
|
|
specific heat capacity, specific entropy
|
|
T} J K⁻¹ kg⁻¹ m² s⁻² K⁻¹
|
|
T{
|
|
thermal conductivity
|
|
T} W m⁻¹ K⁻¹ kg m s⁻³ K⁻¹
|
|
T{
|
|
electric field strength
|
|
T} V m⁻¹ kg m⁻¹ s⁻³ A⁻¹
|
|
permittivity F m⁻¹ kg⁻¹ m⁻³ s⁴ A²
|
|
permeability H m⁻¹ kg m s⁻² A⁻²
|
|
T{
|
|
radiant intensity
|
|
T} W sr⁻¹ kg m² s⁻³
|
|
radiance W sr⁻¹ m⁻² kg s⁻³
|
|
.TE
|
|
The source gives more examples.
|
|
.Sh NON-SI UNITS ACCEPTED FOR USE IN SI
|
|
.TS
|
|
allbox;
|
|
l l c r.
|
|
Quantity Name Sym. Value
|
|
time minute min 1 min = 60 s
|
|
\^ hour h 1 h = 60 min = 3600 s
|
|
\^ day d 1 d = 24 h = 86400 s
|
|
length T{
|
|
astronomical unit
|
|
T} au T{
|
|
1 au = 149 597 870 700 m
|
|
T}
|
|
angle degree \(de 1\(de = (\(*p/180) rad
|
|
\^ minute \(fm T{
|
|
1\(fm = (1/60)\(de = (\(*p/10 800) rad
|
|
T}
|
|
\^ second \(sd T{
|
|
1\(sd = (1/60)\(de = (\(*p/648 000) rad
|
|
T}
|
|
area hectare ha 1 ha = 1 hm² = 10⁴ m²
|
|
volume liter L 1 L = 1 dm³ = 10³ cm³ = 10⁻³ m³
|
|
mass metric ton t 1 t = 10³ kg
|
|
\^ dalton Da 1 Da = 1.660 539 040 (20) E-27 kg
|
|
energy electronvolt eV 1 eV = 1.602 176 634 e-19 J
|
|
T{
|
|
logarithmic quantities
|
|
T} neper Np natural log
|
|
\^ bel B base-10 log
|
|
\^ decibel dB 1 dB = 10⁻¹ B
|
|
.TE
|
|
.Sh NOT-ACCEPTABLE NON-SI UNITS STILL IN USE
|
|
.TS
|
|
allbox;
|
|
l l c r.
|
|
Quantity Name Sym. Value
|
|
length ångström \(oA 10⁻¹⁰ m
|
|
\^ micron \(*m 1 \(*mm
|
|
\^ parsec pc 1 pc = 3.085 678E+16 m
|
|
T{
|
|
radiation dose
|
|
T} rad rad OR rd 1 rd = 10⁻² Gy
|
|
pressure T{
|
|
millimeter of mercury
|
|
T} mmHg 1 mmHg \(=~ 133.322 Pa
|
|
T{
|
|
magnetic flux density
|
|
T} gauss G OR Gs 1 G = 100 μT
|
|
.TE
|
|
.Sh INFO
|
|
This file is public domain. Manual page version 1.0.
|