Pls ans 9th question with solution

Dear Student,
Young's modulus of a wire, $Y=\frac{stress}{strain}=\frac{F}{A}\times \frac{L}{∆L}$
When the length of the wire is doubled, then for the same force F the elongation in length will be $2∆L$,. Hence,
$Y\text{'}=\frac{F}{A}\times \frac{2L}{2∆L}=Y$
So, when the length of the wire is doubled the Young's modulus of the wire remians unchanged.

Poisson’s ratio is the negative of the ratio of transverse strain to lateral or axial strain. Its value varies from -1 to +0,5.
Negative Poisson's ratio show tensile deformation in transverse direction while positive Poisson's ratio show compressive deformation in the transverse direction.
Inelastic materials like concrete, glass, etc., have low +ve Poisson's ratio while elastic materials like, steel, rubber, etc., have high +ve Poisson's ratio.
Ans is (4)
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