Which SI unit is used to measure energy?

• A. kelvin
• B. newton
• C. joule
• D. watt

Answer: (C)

Verified step by step guidance

1. Understand that energy is a physical quantity that represents the capacity to do work or produce heat.
2. Recall the SI base units and derived units related to physical quantities: kelvin (K) measures temperature, newton (N) measures force, watt (W) measures power, and joule (J) measures energy.
3. Recognize that the joule (J) is defined as the amount of energy transferred when a force of one newton moves an object one meter in the direction of the force.
4. Express the joule in terms of base SI units: \(\text{J} = \text{N} \cdot \text{m} = (\text{kg} \cdot \text{m/s}^2) \cdot \text{m} = \text{kg} \cdot \text{m}^2 / \text{s}^2\).
5. Conclude that the SI unit used to measure energy is the joule (J).