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Joule
Joule
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 SI multiples for joule (J) 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
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 SI multiples for joule (J) 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
- For additional examples, see: Orders of magnitude (energy)
- The work required to move an electric charge of one coulomb through an electrical potential difference of one volt, or one '"coulomb volt" (C·V). This relationship can be used to define the volt.
- The work required to produce one watt of power for one second, or one "watt second" (W·s) (compare kilowatt hour - 3.6 megajoules). This relationship can be used to define the watt.
- The energy required to lift a medium-size tomato (100 g) 1 meter vertically from the surface of the Earth.
- The energy released when that same tomato falls back down to the ground.
- The energy required to accelerate a 1 kg mass at 1 m·s^{−2} through a 1 m distance in space.
- The heat required to raise the temperature of 1 g of water by 0.24 °C.
- The typical energy released as heat by a person at rest every 1/60 second (approximately 17 ms).
- The kinetic energy of a 50 kg human moving very slowly (0.2 m/s or 0.72 km/h).
- The kinetic energy of a 56 g tennis ball moving at 6 m/s (22 km/h).
- The kinetic energy of an object with mass 1 kg moving at √2 ≈ 1.4 m/s.
- The amount of electricity required to light a 1 watt LED for 1 s.
- ×10^{7} erg (exactly) 1
- 50974×10^{18} eV 6.241
- cal (gram calories) 0.2390
- ×10^{−4} kcal (food calories) 2.390
- ×10^{−4} BTU 9.4782
- ft·lb 0.7376
- ft·pdl (foot-poundal) 23.7
- ×10^{−7} kilowatt-hour 2.7778
- ×10^{−4} watt-hour 2.7778
- ×10^{−3} l·atm (litre-atmosphere) 9.8692
- ×10^{−15} gram (by way of 11.1265mass-energy equivalence)
- ×10^{−44} foe (exactly) 1
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Joule