SI Base Units

The International System of Units (SI) define the following base units
 

Meter (m)
The length of the path traveled by light in a vacuum during a time interval of 1/299 792 458 of a second.
 

Kilogram (kg)
Equal to the mass of the international prototype of the kilogram. The prototype is an alloy of 90% platinum and 10% iridium. It was manufactured in the 1880s and kept with its six official copies in a vault at the BIPM.
 

Second (s)
The base unit of time. It is the duration of 9 192 631 770 periods of radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.
 

Ampere (A)
A constant electric current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in a vacuum, would produce between these conductors a force equal to 2 × 10-7 newton per meter of length.
 

Kelvin (K)
The fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
 

Candela (cd)
Unit for luminous intensity. A source that emits monochromatic radiation of frequency 540 × 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.
 

Mole (mol)
Unit for quantity of matter. The amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12.
 

SI Derived Units

Derived quantity Name Symbol Other symbol Base units
plane angle radian rad - m·m-1 = 1
solid angle steradian sr - m2·m-2=1
frequency hertz Hz - s-1
force newton N - m·kg·s-2
pressure,
stress
pascal Pa N/m2 m-1·kg·s-2
energy,
work, quantity of heat
joule J Nm m2·kg·s-2
power,
radiant flux
watt W J/s m2·kg·s-3
electric
charge, quantity of electricity
coulomb C - s·A
electric
potential, difference, electromotive force
volt V W/A m2·kg·s-3·A-1
capacitance farad F C/V m-2·kg-1·s4·A2
electric
conductance
siemens A/V m-2·kg-1·s3·A2
electric resistance ohm W V/A m2·kg·s-3·A-2
magnetic flux weber Wb Vs m2·kg·s-2·A-1
magnetic flux density tesla T Wb/m2 kg·s-2·A-1
inductance henry H Wb/A m2·kg·s-2·A-2
Celsius temperature degree Celsius °C - K
luminous flux lumen lm cd·sr m2·m-2·cd = cd
illuminance lux lx lm/m2 m2·m-4·cd = m-2·cd
activity (of a radionuclide) becquerel Bq - s-1
absorbed dose, specific energy (imparted), kerma gray Gy J/kg m2·s-2
dose equivalent sievert Sv J/kg m2·s-2
catalytic activity katal kat - s-1mol

 

SI Unit Prefixes

Derived quantity Name Symbol Other symbol Base units
plane angle radian rad - m·m-1 = 1
solid angle steradian sr - m2·m-2=1
frequency hertz Hz - s-1
force newton N - m·kg·s-2
pressure,
stress
pascal Pa N/m2 m-1·kg·s-2
energy,
work, quantity of heat
joule J Nm m2·kg·s-2
power,
radiant flux
watt W J/s m2·kg·s-3
electric
charge, quantity of electricity
coulomb C - s·A
electric
potential, difference, electromotive force
volt V W/A m2·kg·s-3·A-1
capacitance farad F C/V m-2·kg-1·s4·A2
electric
conductance
siemens A/V m-2·kg-1·s3·A2
electric resistance ohm W V/A m2·kg·s-3·A-2
magnetic flux weber Wb Vs m2·kg·s-2·A-1
magnetic flux density tesla T Wb/m2 kg·s-2·A-1
inductance henry H Wb/A m2·kg·s-2·A-2
Celsius temperature degree Celsius °C - K
luminous flux lumen lm cd·sr m2·m-2·cd = cd
illuminance lux lx lm/m2 m2·m-4·cd = m-2·cd
activity (of a radionuclide) becquerel Bq - s-1
absorbed dose, specific energy (imparted), kerma gray Gy J/kg m2·s-2
dose equivalent sievert Sv J/kg m2·s-2
catalytic activity katal kat - s-1mol

 

The US Customary System of Measures

The following are the English System of measurement
 

Length
12 inches = 1 foot
3 feet = 1 yard
220 yards = 1 furlong
8 furlongs = 1 mile
5 280 feet = 1 mile
1 760 yards = 1 mile
 

Area
144 square inches = 1 square foot
9 square feet = 1 square yard
4 840 square yards = 1 acre
640 acres = 1 square mile
1 square mile = 1 section
36 sections = 1 township
 

Volume
1,728 cubic inches = 1 cubic foot
27 cubic feet = 1 cubic yard
 

Mass
437.5 grains = 1 ounce
16 ounces = 1 pound
14 pounds = 1 stone
100 pounds = 1 hundredweight
20 hundredweights = 1 ton
 

Capacity (Dry)
16 fluid ounces = 1 pint
2 pints = 1 quart
8 quarts = 1 peck
4 pecks = 1 bushel
 

Capacity (Liquid)
4 gills = 1 pint
2 pints = 1 quart
4 quarts = 1 gallon
 

Apothecaries' Measures
60 minims = 1 fluid dram
8 fluid drams = 1 fluid ounce
16 fluid ounces = 1 pint
 

Apothecaries' Weights
20 grains = 1 scruple
3 scruples = 1 dram
8 drams = 1 ounce
 

Troy Weights
24 grains = 1 pennyweight
20 pennyweights = 1 ounce
 

0 likes