Joule
Definition: (j?l, joul) , abbr. J, unit of work or energy in the mks system of units, which is based on the metric system; it is the work done or energy expended by a force of 1 newton acting through a distance of 1 meter. The joule is named for James P. Joule.
One joule is the work done, or energy expended, by a force of one newton moving an object one metre 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:
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.
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.
