Standard: | SI derived unit |
Quantity: | Energy |
Symbol: | J |
Named after: | James Prescott Joule |
Expressed in: | 1 J = |
SI base units | 1 kg·m2/s2 |
CGS units | 1×107 erg |
kilowatt hours | 2.78×10−7 kW·h |
kilocalories | 2.39×10−4 kcal |
BTUs | 9.48×10−4 BTU |
A joule (/ˈdʒaʊl/ or sometimes /ˈdʒuːl/) is a unit in the SI system. It measures energy; usually in scientific or electrical appliances . It is named after James Prescott Joule.
A joule refers to the amount of energy transferred to an object when a force of 1 newton is applied on it over a distance of 1 metre (1J = 1N × 1m). It is related to the watt (a unit of power): one watt equals one joule per second.