Case: Read the passage and answer the question.
An atom contains a dense mass at its centre, called the nucleus. The nucleus is positively charged and is made up of neutrons and protons. Therefore, it may be expected that the mass of the nucleus is equal to the total mass of its individual protons and neutrons. However, the nuclear mass M is found to be always less than this.
If a certain number of neutrons and protons are brought together to form a nucleus, a fixed amount of energy is associated with it. What is it called?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Binding energy
NCERT (2026-27):
Nuclear Binding Energy – “If a certain number of neutrons and protons are brought together to form a nucleus of a certain charge and mass, an energy Eb will be released in the process. The energy Eb is called the binding energy of the nucleus. If we separate a nucleus into its nucleons, we would have to supply a total energy equal to Eb, to those particles.”