Joule

For the physicist, seeJames Prescott Joule.

Joule
Unit system	SI derived unit
Unit of	Energy
Symbol	J
Named after	James Prescott Joule
Conversions
1 J in...	... is equal to...
SI base units	1kg·m2/s2
CGS units	1×107erg
kilowatt hours	2.78×10−7kW⋅h
kilocalories	2.39×10−4kcal
BTUs	9.48×10−4BTU
electronvolts	6.24×1018eV

Ajoule(/ˈdʒaʊl/or sometimes/ˈdʒuːl/) is aunitin theSIsystem. It measures energy; usually in scientific or electrical appliances. It is named afterJames Prescott Joule.

A joule refers to the amount of energy transferred to an object when a force of 1newtonis applied on it over a distance of 1metre(1J = 1N × 1m). It is related to thewatt(a unit ofpower): one watt equals one joule per second.

It can also be understood as the work done for passing one ampere ofelectric currentthrough anelectric circuitof external resistance equivalent to one ohm for one second.