Joule (J)

Quantity: Energy / Work · Category: Derived SI

The joule is the SI unit of energy and work: the energy transferred when a force of one newton moves an object one meter. It is named after James Prescott Joule, who established the mechanical equivalent of heat.

Relation to SI

1 J = 1 N·m = 1 kg·m²/s²

Examples

• Lifting an apple one meter takes about 1 joule.
• A 100 W light bulb uses 100 joules every second.