Question

Choose the most elastic substance from the following option.
A.Rubber
B.Nylon
C.Steel
D.Iron

Answer 1

Elasticity is that property of any solid material by which it regains its original shape and size whenever the deforming force is removed from it, by which it was getting deformed or losing it’s original shape and size.

Complete step by step answer:
By definition given in hint, the substance which are more likely to regain their original shape and size, have more elasticity than those, who are less likely to regain their original shape and size than previous substance.

Elasticity of materials is measured in terms of Young’s Modulus (or elastic modulus). Young's modulus is calculated by dividing the stress by the strain where stress is the force developed on material per unit area and strain is the relative change in size of the material.
Therefore,
${\text{Stress = }}\dfrac{{\text{F}}}{A}$
Where, $F$ is the deforming force applied to material and,
$A$ is the total area of material
And,
${\text{Strain = }}\dfrac{{\Delta l}}{L}$
Where, $\Delta l$ is the change in length of material and,
$L$ is the total length of material.
Now, we know that,
${\text{Young's Modulus = }}\dfrac{{{\text{Stress}}}}{{{\text{Strain}}}}$
So we get Young’s Modulus as,
$Y = \dfrac{{\dfrac{F}{A}}}{{\dfrac{{\Delta l}}{L}}}$
Where $Y$ is Young’s Modulus of material,
So we get,
$Y = \dfrac{{FL}}{{A\Delta l}}$
Now, suppose we are applying the same force of all materials, rubber, nylon, steel and iron of the same length and area. Then, we will observe that the maximum change in length will be in Steel.
Which in turn gives us the result that steel will have the maximum Young’s Modulus compared to others hence, is more elastic than other given options.
Hence, the correct answer is option (C).

Note: Although elasticity is the ability of regaining original shape and size, it does not depend on the shape and size of the material. It only depends on the type or nature of material and the type of force or stress used to deform material.