## SI UNIT CONVERSION

SI DEFINED UNITS
Quantity Name Symbol
length (distance) meter m
mass kilogram kg
time second s
temperature Kelvin K
current Ampere A
quantity mole mol
luminosity candela cd
SI DERIVED UNITS
Quantity Name Symbol Units
frequency Hertz Hz m-1
velocity - - m s-1
acceleration - - m s-2
force Newton N kg m s-2
pressure (stress) Pascal Pa N m-2 = kg m-1 s-2
energy (work, heat) Joule J N m = kg m2 s-2
momentum (impulse) - - N s = kg m s-1
power Watt W J s -1 = kg m2 s-3
electric charge Coulomb C A s
electric potential (emf) Volt V J C-1 = W A -1 = kg m2 s-3 A-1
resistance Ohm W V A-1 = kg m2 s-3 A-2
conductance Siemens S A V-1 = W-1 = kg-1 m-2 s3 A2
magnetic flux Weber Wb V s = kg m2 s-2 A -1
inductance Henry H Wb A-1 = kg m2 s-2 A-2
capacitance Farad F C V-1 = kg-1 m-2 s4 A2
electric field strength - - V m-1 = N C-1
electric displacement - - C m-2
magnetic field strength - - A m-1
magnetic flux density Tesla T Wb m-2 = N A-1 m-1 = kg s-2 A-1
solid angle steradian sr 4p (sphere)
luminous flux lumen lm cd sr
illuminance lux lx lm m²
SI ACCEPTED UNITS
Quantity Name Symbol Units
length Ångstrom Å,å 1 a = 10-10 m
volume Liter L, l 1 L = 10-3 m³
mass metric ton t 1 t = 1000 kg
pressure bar bar 1 bar = 105 Pa = 105 N m-2
time minute min 1 min = 60 sec
time hour h 1 h = 60 min = 3600 sec
time day d 1 d = 24 h = 86 400 sec
plane angle degree o 1o = (p/180) rad
plane angle minute ' 1' = (1/60)o = (p/10 800) rad
plane angle second " 1" = (1/60)' = (p /648 000) rad
GEOMETRIC CONSTANTS
EARTH CONSTANTS
Constant Symbol Value
Standard Atmosphere atm 101 325 Pa (exact)
Standard Acceleration of Gravity ga 9.806 65 m s-2 (exact)
Astronomical Unit (Earth-Sun) au 1.495 978 706 91 (30) 1011 m
PLANCK CONSTANTS
Constant Symbol Value
Planck Constant h 6.626 075 5 10 (40) 10-34 J s
Planck Constant = h/{e} (in electron Volts) h/{e } 4.135 669 2 (12) 10-15 eV s
Planck Constant = h/2p h 1.054 572 66 (63) 10-34 J s
Planck Constant = h/2p{e} (in electron Volts) h/{e} 6.582 122 0 (20) 10-16 eV s
Planck Mass = (hc/G)1/2 mP 2.176 71 (14) 10-8 kg
Planck Length = h/mPc = (hG/c3)1/2 l P 1.616 05 (10) 10-35 m
Planck Time = lP/c = (hG/c5)1/2 tP 5.390 56 (34) 10 -44 s
RYDBERG CONSTANTS
Constant Symbol Value
Rydberg Constant = meca²/2h 10 973 731.534 (13) m-1
Rydberg Constant = RɎ c (in Hertz) RɎc 3.289 841 949 9 (40) 1015 Hz
Rydberg Constant = RɎhc (in Joules) RɎhc 2.179 874 1 (13) 10-18 J
Rydberg Constant = RɎ hc/{e} (in electron Volts) RɎhc/{e} 13.605 698 1 (40) eV
PHYSICAL CONSTANTS
Constant Symbol Value
Bohr Radius = a/4pR Ɏ ao 0.529 177 249 (24) 10-10 m
Hartree Energy = e2/4peoao = 2RɎhc Eh 4.359 748 2 (26) 10-18 J
Hartree Energy = Eh/{e} (in electron Volts) Eh/{e} 27.211 396 1 (81) eV
Quantum of Circulation = h/2me h/2me 3.636 948 07 (33) 10-4 m2 s-1
Quanta of Circulation = h/m e h/me 7.273 896 14 (65) 10-4 m² s-1
CHEMICAL CONSTANTS
Constant Symbol Value
Avogadro's number N A, L 6.022 136 7 (36) 1023 mol-1
Atomic Mass Constant = m(12C)/12 = 1 Dalton (Da) mu 1.660 540 2 (10) 10-27 kg
Atomic Mass Constant = muc²/{e} (in electron Volts) mu 931.494 32 (28) MeV
Faraday Constant F 96 485.309 (29) C mol -1
Molar Planck Constant = NA h NAh 3.990 313 23 (36) 10-10 J s mol-1
Molar Planck Constant = NAhc NAhc 0.119 626 58 (11) J m mol-1
Molar Gas Constant R 8.314 510 (70) J mol-1 K-1
Molar Volume = RT/p (ideal gas at 1 atm/273.15 K) Vm 22 414.10 (19) cm³ mol-1
Loschmidt Constant = NA/Vm no 2.686 763 (23) 1025 m³

The 20 SI prefixes used to form decimal multiples and submultiples of SI units are given below:-

FACTOR NAME SYMBOL
1024 yotta Y
1021 zetta Z
1018 exa E
1015 peta P
1012 tera T
109 giga G
106 mega M
103 kilo k
102 hecto h
101 deka da
10-1 deci d
10-2 centi c
10-3 milli m
10-6 micro ?
10-9 nano n
10-12 pico p
10-15 femto f
10-18 atto a
10-21 zepto z
10-24 yocto y

It is important to note that the kilogram is the only SI unit with a prefix as part of its name and symbol. Because multiple prefixes may not be used, in the case of the kilogram the prefix names of Table?5 are used with the unit name "gram" and the prefix symbols are used with the unit symbol "g." With this exception, any SI prefix may be used with any SI unit, including the degree Celsius and its symbol ?C.

Example 1:10-6 kg = 1 mg (one milligram), but not 10-6 kg = 1 ?kg (one microkilogram)