Which of the following is NOT a form of energy listed among common energy forms?

• A. Sound Energy
• B. Nuclear Energy
• C. Light Energy
• D. Mass

Answer: (D)

Energy comes in different forms that describe how it exists or can be transferred. Sound energy comes from vibrating objects producing pressure waves in the air. Nuclear energy is the energy stored in atomic nuclei that can be released in reactions. Light energy is energy carried by photons of electromagnetic radiation that we can see as light. Mass, on the other hand, is a property of matter—the amount of matter something contains. It isn’t a way energy exists, even though mass can be converted into energy in principle (mass-energy equivalence). Because mass is not an energy form, it is the correct answer.