Mass-energy equivalence in fission relates to?

• A. The mass defect is converted to energy per Einstein's E=mc^2, about 200 MeV.
• B. No relation to energy.
• C. Energy is created without mass change.
• D. Energy is consumed reducing mass.

Answer: (A)

Mass-energy equivalence in fission hinges on the fact that the total rest mass of the fission fragments is smaller than the rest mass of the original nucleus. That missing mass, the mass defect, is converted into energy according to E = mc^2, which is why fission releases a substantial amount of energy—about 200 MeV per event. That energy manifests primarily as the kinetic energy of the fragments and emitted radiation.

If there were no relation to energy, or if energy could be created without a mass change, or if energy were consumed to reduce mass, it would contradict the observed energetic release of fission. The key point is that the released energy comes from the decrease in mass, not from creating energy from nothing or consuming energy to diminish mass.