Define 'binding energy'. Sketch the graph between binding energy per nucleon and mass number.

Explanation

### Step-by-Step Solution:

1. **Definition of Binding Energy**:
- Binding energy is defined as the energy required to hold the nucleons (protons and neutrons) together in the nucleus of an atom. It represents the stability of the nucleus; a higher binding energy indicates a more stable nucleus.

2. **Understanding Nucleons**:
- Nucleons are the particles found in the nucleus of an atom. They include protons (positively charged) and neutrons (neutral). The binding energy is the energy needed to overcome the forces that hold these nucleons together.

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