Which of the following is the SI unit of energy?

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

Answer: (D)

Verified step by step guidance

1. Understand that energy is a physical quantity that measures the capacity to do work or produce heat.
2. Recall that the SI (International System of Units) unit for energy is defined based on the unit of work, which is force times distance.
3. Know that the SI unit of force is the newton (N), and the SI unit of distance is the meter (m).
4. Use the relationship for work or energy: \(\text{Energy} = \text{Force} \times \text{Distance}\), which in SI units is \(\text{joule} = \text{newton} \times \text{meter}\).
5. Recognize that the joule (J) is the SI unit of energy, while watt is a unit of power, calorie is a non-SI unit of energy, and newton is a unit of force.