Correct Answer - Option 3 : 0.25

**Concept:**

Relation between modulus of rigidity (**G**), young’s modulus (**E**) & Poisson’s ratio (**μ**) is

**E=2G(1+μ)**

**Calculation:**

__Given:__

\(\frac {{G}}{{E}} \) = 0.4

E = 2G (1 + μ)

\(\frac {{E}}{{G}} \) = 2 (1 + μ)

\(\frac {{1}}{{0.4}} \) = 2 (1 + μ)

1.25 = 1 + μ

**μ = 0.25 **

Other relations between elastic constants

**E = \( \frac {{9KG}}{{3K+G}}\)**

**E = 3K (1 - 2μ)**