# User Contributed Dictionary

# Extensive Definition

The joule ( or /ˈdʒaʊl/) (symbol: J) is the SI unit of
energy measuring heat,
electricity and
mechanical
work. It was named after English physicist James
Prescott Joule.

## Description

One joule is the work done, or energy expended, by a force of one newton moving one metre along the direction of the force. This quantity is also denoted as a newton metre with the symbol N·m. Note that torque also has the same units as work, but the quantities are not the same. In elementary units:- \, 1\, \mathrm=1\, \mathrm \cdot \mathrm

- \, 1\, \mathrm=1\, \mathrm \cdot \frac

One joule is also:

- The work required to move an electric charge of one coulomb through an electrical potential difference of one volt; or one coulomb volt, with the symbol C·V.
- The work done to produce power of one watt continuously for one second; or one watt second (compare kilowatt hour), with the symbol W·s. Thus a kilowatt hour is 3,600,000 joules or 3.6 megajoules

## History

A joule is the mechanical equivalent of heat
meaning the number of units of work in which the unit of heat can
perform. Its value was found by James
Prescott Joule in experiments that showed the mechanical energy
Joule's equivalent, and represented by the symbol J. The term was
first introduced by Dr. Mayer of Heilbronn.

## Conversions

1 joule is exactly 107 ergs.1 joule is approximately equal to:

- 6.2415 eV (electronvolts)
- 0.2390 cal (calorie) (small calories, lower case c)
- 2.3901 kilocalorie, Calories (food energy, upper case C)
- 9.4782 BTU (British thermal unit)
- 0.7376 ft·lbf (foot-pound force)
- 23.7 ft·pdl (foot poundals)
- 2.7778 kilowatt hour
- 2.7778 watt hour
- 9.8692 litre-atmosphere

1 joule in everyday life is approximately:

- the energy required to lift a small apple one metre straight up.
- the energy released when that same apple falls one meter to the ground.
- the amount of energy, as heat, that a quiet person generates every hundredth of a second.
- the energy required to heat one gram of dry, cool air by 1 degree Celsius.
- one hundredth of the energy a person can get by drinking a single drop of beer.
- the kinetic energy of an adult human moving a distance of about a handspan every second.

Units defined in terms of the joule include:

- 1 thermochemical calorie = 4.184 J
- 1 International Table calorie = 4.1868 J
- 1 watt hour = 3600 J
- 1 kilowatt hour = 3.6 J (or 3.6 MJ)
- 1 ton TNT = 4.184 GJ

Useful to remember:

- 1 joule = 1 newton metre = 1 watt second

### SI multiples

## See also

## References

- The adoption of joules as units of energy, FAO/WHO Ad Hoc Committee of Experts on Energy and Protein, 1971. A report on the changeover from calories to joules in nutrition.

## External links

kilojoule in Afrikaans: Joule

kilojoule in Arabic: جول

kilojoule in Asturian: Xuliu (unidá)

kilojoule in Bengali: জুল

kilojoule in Belarusian: Джоўль

kilojoule in Belarusian (Tarashkevitsa):
Джоўль

kilojoule in Bosnian: Džul

kilojoule in Bulgarian: Джаул

kilojoule in Catalan: Joule

kilojoule in Czech: Joule

kilojoule in Danish: Joule

kilojoule in German: Joule

kilojoule in Estonian: Džaul

kilojoule in Modern Greek (1453-): Τζάουλ
(μονάδα μέτρησης)

kilojoule in Spanish: Julio (unidad)

kilojoule in Esperanto: Ĵulo

kilojoule in Basque: Joule (unitatea)

kilojoule in Persian: ژول

kilojoule in French: Joule

kilojoule in Scottish Gaelic: Joule

kilojoule in Galician: Joule (unidade)

kilojoule in Korean: 줄 (단위)

kilojoule in Croatian: Džul

kilojoule in Indonesian: Joule

kilojoule in Icelandic: Júl

kilojoule in Italian: Joule

kilojoule in Hebrew: ג'ול

kilojoule in Swahili (macrolanguage):
Jouli

kilojoule in Latin: Joulium

kilojoule in Latvian: Džouls

kilojoule in Lithuanian: Džaulis

kilojoule in Hungarian: Joule

kilojoule in Malay (macrolanguage): Joule

kilojoule in Dutch: Joule

kilojoule in Japanese: ジュール

kilojoule in Norwegian: Joule

kilojoule in Norwegian Nynorsk: Joule

kilojoule in Occitan (post 1500): Joule

kilojoule in Polish: Dżul

kilojoule in Portuguese: Joule

kilojoule in Kölsch: Joule (Mohß)

kilojoule in Romanian: Joule

kilojoule in Russian: Джоуль

kilojoule in Simple English: Joule

kilojoule in Slovak: Joule

kilojoule in Slovenian: Džul

kilojoule in Serbian: Џул

kilojoule in Finnish: Joule

kilojoule in Swedish: Joule

kilojoule in Thai: จูล

kilojoule in Vietnamese: Joule

kilojoule in Turkish: Joule (birim)

kilojoule in Ukrainian: Джоуль

kilojoule in Urdu: جاؤل

kilojoule in Venetian: Joule

kilojoule in Chinese: 焦耳