Poisson’s ratio of a stable, isotropic, linear elastic material lies in the range - 1 < $\sigma$ < 0.5, theoretically. For most of the materials $\sigma$ < 0.5. This is because, moduli of elasticity should have positive values. Negative Poisson’s ratio in DESIGNED materials and in some anisotropic materials has been observed. $\therefore \,$ For most of the materials $\sigma$ < 0.5. $\therefore \,$