What are the theoritical units of Poission.s ratio? What are the practical limits of poission ratio ?

Explanation

### Step-by-Step Solution:

1. **Understanding Poisson's Ratio**:
- Poisson's ratio (ν) is defined as the ratio of the transverse strain to the axial strain when a material is subjected to uniaxial stress.
- Mathematically, it is expressed as:
\[ \nu = -\frac{\text{Transverse Strain}}{\text{Axial Strain}} = -\frac{\Delta d / d}{\Delta L / L} \]
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