Answer;
B. mass being converted to energy when protons and neutrons bind together in a nucleus
Step-by-step explanation;
- The mass defect of a nucleus refers to the mass of the energy binding the nucleus. This energy is given by the difference between the mass of a nucleus and the sum of the masses of the nucleons of which it is composed.
- Mass defect is energy mass that is removed from the total mass of the original particles when a nucleus is formed. This mass is missing in the resulting nucleus and represent the energy lost when the nucleus is formed.