Refrigeration Operator Level 1 Practice Exam 2026 - Free Refrigeration Operator Practice Questions and Study Guide

The SI unit of measure for energy is the Joule. Named after the English physicist James Prescott Joule, the Joule is defined as the amount of energy transferred when a force of one newton is applied over a distance of one meter. This defines its relationship to both force and distance, which is fundamental in physics.

Joules are commonly used in various contexts, including mechanical work, heat transfer, and electrical energy. For instance, when calculating the amount of energy consumed by electrical appliances, the kilowatt-hour is a related derivative, but it ultimately boils down to Joules.

In contrast, while Watts is a unit of power (indicating the rate at which energy is used or produced), Newton is a unit of force, and Calorie is often used in the context of heat energy but is not the standard SI unit. The Calorie itself is equal to approximately 4.184 Joules, but again, it is not the primary SI unit defined for measuring energy. Thus, the choice of Joule as the answer reflects its standing as the standard unit within the International System of Units.