What is the basic unit of all energy?

The correct answer is Joule, which is the fundamental unit of energy in the International System of Units (SI). It is defined as the amount of energy transferred when a force of one newton is applied over a distance of one meter. This basic unit encompasses various forms of energy, including mechanical, thermal, and electrical energy. Understanding the Joule is crucial for anyone working in fields related to energy, including refrigeration, as it provides a clear and standardized way to measure and relate energy quantities across different systems and processes.

While watts, calories, and volts are all important units in their respective contexts, they are not the basic units of energy. Watts measure power (the rate of energy transfer), calories are often used to quantify heat energy, and volts measure electric potential difference. Each of these units relates to energy in specific situations but does not serve as the foundational unit of energy itself like the Joule does. This makes the Joule a key concept for anyone studying or working within the energy sector.