The joule ( or sometimes ); symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended (or work done) in applying a force of one newton through a distance of one meter (1 newton metre or N·m), or in passing an electric  current of one ampere through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889).