Which of the following SI units is used to measure energy?

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

Answer: (A)

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 unit definitions: kelvin (K) is the unit of temperature, watt (W) is the unit of power (rate of energy transfer), and newton (N) is the unit of force.
3. Identify that the SI unit used to measure energy is the joule (J), which is defined as the amount of work done 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: \(\text{J} = \text{N} \cdot \text{m} = \text{kg} \cdot \text{m}^2 / \text{s}^2\).
5. Conclude that among the given options, the joule is the correct SI unit for measuring energy.