The joule (symbol: J) is the SI unit of energy. It was named after James Prescott Joule for his work on the relationship between heat, electricity and mechanical work.
One joule is the work done, or energy expended, by a force of one newton moving an object one meter along the direction of the force. This quantity is also denoted as a Newton-meter with the symbol N·m. Note that torque also has the same units as work, but the quantities are not identical. In elementary units:
1J = 1kg. m²/s²
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.
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