which point defect in crystals of a solid does not change the density of the soild ?

Explanation

To determine which point defect in crystals of a solid does not change the density of the solid, we need to analyze the different types of point defects and their effects on density.

### Step-by-Step Solution:

1. **Understanding Point Defects**: Point defects are irregularities in the crystal lattice that occur at a single lattice point. The main types of point defects include vacancies, interstitials, and substitutional defects.

2. **Types of Point Defects**:
- **Vacancy Defect**: This occurs when an atom is missing from its lattice site. This decreases the density because there are fewer atoms in the same volume.
...