Packing fraction of a nucleus is defined as..............per............. .

Answer

To solve the question regarding the definition of the packing fraction of a nucleus, we can break it down into a few clear steps:

### Step-by-Step Solution:

1. **Understanding the Concept**: The packing fraction of a nucleus relates to how the mass of individual nucleons (protons and neutrons) changes when they come together to form a nucleus.

2. **Identifying the Terms**: The packing fraction is a measure that compares the mass of a nucleus to the total mass of its constituent nucleons if they were separate.

3. **Filling in the Blanks**: The packing fraction of a nucleus can be defined as the mass of the nucleus divided by the total mass of the individual nucleons that make it up.

4. **Final Definition**: Therefore, we can fill in the blanks as follows:
- Packing Fraction of a Nucleus is defined as **mass of the nucleus** per **total mass of nucleons**.

### Complete Answer:
Packing Fraction of a nucleus is defined as **mass of the nucleus** per **total mass of nucleons**.