Question

The Poisson's ratio of a material whose Young's modulus is 1.2 × 10⁵ N/mm² and modulus of rigidity is 4.8 × 10⁴ N/mm², is:
1. 2.25
2. 1.25
3. 0.25
4. 0.5

Answer 1

Correct Answer - Option 3 : 0.25

Concept:

Relation between different elastic constants E,μ,K and G are

• E = 2G (1 + μ)
• E = 3K (1 - 2μ)

Where E = young's modulus, μ = Poisson's ratio, K = bulk modulus, G = modulus of rigidity

​Calculation:

Given: 

Young's modulus (E) = 1.2 × 105 N/mm2 and modulus of rigidity (G) = 4.8 × 104 N/mm2

E = 2G (1 + μ)

1.2 × 10⁵  = 2 × 4.8 × 10⁴ (1 + μ)

1.25 = 1 + μ

μ = 0.25