Define binding energy of a nucleus.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Structure of an Atom**:
- An atom consists of a nucleus at its center, which is made up of protons (positively charged) and neutrons (neutral). Electrons (negatively charged) revolve around this nucleus in circular orbits.

2. **Defining Binding Energy**:
- The binding energy of a nucleus refers to the energy that is required to disassemble the nucleus into its individual protons and neutrons.

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