Which term best describes the energy release when a heavy nucleus splits into smaller parts?

Which term best describes the energy release when a heavy nucleus splits into smaller parts?

• A. Nuclear Fusion
• B. Mass defect
• C. Decay Constant
• D. Nuclear Fission

Answer: (D)

Nuclear fission is the splitting of a heavy nucleus into lighter parts. When this happens, the resulting fragments are more tightly bound on average, so the system lowers its overall energy by releasing that excess energy as kinetic energy of the fragments and radiation. The energy release also corresponds to a small loss of mass, known as the mass defect, which is converted into energy according to E = mc^2. This combination—the process of splitting a heavy nucleus and the associated energy release—defines fission. Fusion, by contrast, joins light nuclei to form heavier ones, not splits. The mass defect concept explains where the energy comes from, but it’s not the name of the process. The decay constant describes how fast radioactive decay occurs, not the energy released in fission.

Nuclear fission is the splitting of a heavy nucleus into lighter parts. When this happens, the resulting fragments are more tightly bound on average, so the system lowers its overall energy by releasing that excess energy as kinetic energy of the fragments and radiation. The energy release also corresponds to a small loss of mass, known as the mass defect, which is converted into energy according to E = mc^2. This combination—the process of splitting a heavy nucleus and the associated energy release—defines fission.

Fusion, by contrast, joins light nuclei to form heavier ones, not splits. The mass defect concept explains where the energy comes from, but it’s not the name of the process. The decay constant describes how fast radioactive decay occurs, not the energy released in fission.