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.