Joule (J) is the unit of electrical, mechanical and thermal energy in the international system of units
.As electrical energy, one joule is equal to the work done
, which inturn is equal to 860 calories (cal).
This irreversible generation of energy, based on thermoelectricity, is also known as the Joule effect. The joule is named after the British physicist James Prescott Joule (1818 - 1889).