(a) We know that the Poisson’s ratio have the theoretical value
$- 1 < \sigma < \frac{1}{2}$
But practically the value of $\sigma$ (Poisson’s ratio) is
$0 < \sigma < \frac{1}{2}$
So the Poisson’s ratio cannot have the value 0.7.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.