Question

The formula $Y=3B(1-2\sigma )$ relates young's modulus and bulk's modulus with poisson's ratio. A theoretical physicist derives this formula incorrectly as $Y=3B(1-4\sigma )$. According to this formula, what would be the theoretical limits of poisson's ratio:

• A. Poisson's ratio should be less than 1
• B. Poisson's ratio should be less than 0.5
• C. Poisson's ratio should be less than 0.25
• D. Poisson's ratio should be less than 0

Answer 1

The correct option is C Poisson's ratio should be less than 0.25

In the formula derived by the student, in order that Y is positive, $\sigma <0.25$, else Y will be negative, which is not possible
Hence, poisson's ratio should be less than 0.25
The correct option is option(c)