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Joule  

Unit system  SI derived unit 
Unit of  Energy 
Symbol  J 
Named after  James Prescott Joule 
1 J in ...  ... is equal to ... 
SI base units  kg⋅m^{2}⋅s^{−2} 
CGS units  ×10^{7} 1erg 
kilowatt hours  ×10^{−7} kW⋅h 2.78 
kilocalories (thermochemical)  ×10^{−4} kcal_{th} 2.390 
BTUs  ×10^{−4} BTU 9.48 
electronvolts  ×10^{18} eV 6.24 

The joule (/ˈdʒuːl/), symbol J, is a derived unit of energy in the International System of Units. It is equal to the energy transferred to (or work done on) an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or N·m). It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889).
In terms firstly of base SI units and then in terms of other SI units:
where kg is the kilogram, m is the metre, s is the second, N is the newton, Pa is the pascal, W is the watt, C is the coulomb, and V is the volt.
One joule can also be defined as:
This SI unit is named after James Prescott Joule. As with every International System of Units (SI) unit named for a person, the first letter of its symbol is upper case (J). However, when an SI unit is spelled out in English, it should always begin with a lower case letter (joule)—except in a situation where any word in that position would be capitalized, such as at the beginning of a sentence or in material using title case. Note that "degree Celsius" conforms to this rule because the "d" is lowercase.— Based on The International System of Units, section 5.2.
Linear  Angular 

force  torque 
mass  moment of inertia 
distance  angle 
Submultiples  Multiples  

Value  SI symbol  Name  Value  SI symbol  Name  
10^{−1} J  dJ  decijoule  10^{1} J  daJ  decajoule  
10^{−2} J  cJ  centijoule  10^{2} J  hJ  hectojoule  
10^{−3} J  mJ  millijoule  10^{3} J  kJ  kilojoule  
10^{−6} J  µJ  microjoule  10^{6} J  MJ  megajoule  
10^{−9} J  nJ  nanojoule  10^{9} J  GJ  gigajoule  
10^{−12} J  pJ  picojoule  10^{12} J  TJ  terajoule  
10^{−15} J  fJ  femtojoule  10^{15} J  PJ  petajoule  
10^{−18} J  aJ  attojoule  10^{18} J  EJ  exajoule  
10^{−21} J  zJ  zeptojoule  10^{21} J  ZJ  zettajoule  
10^{−24} J  yJ  yoctojoule  10^{24} J  YJ  yottajoule  
Common multiples are in bold face 
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