What is the SI unit of energy?

• A. Calorie
• B. Joule
• C. Electronvolt
• D. Newton

Answer: (B)

The SI unit of energy is the joule. This unit is defined as the amount of energy transferred when a force of one newton is applied over a distance of one meter. The joule is a standardized unit used in various scientific disciplines to quantify energy, work, and heat.

When considering the other options, a calorie is a unit of energy commonly used in the context of food and nutrition, but it is not part of the International System of Units (SI). The electronvolt is a unit of energy used primarily in the field of particle physics, but it is also not an SI unit. A newton, while related to energy through its definition, is a unit of force, not energy. Thus, the joule stands out as the correct answer, being the definitive SI unit that is widely recognized and used in scientific measurements of energy.