Young's Modulus (E) is a measure of the stiffness or elastic modulus of a material. It is defined as the ratio of tensile or compressive stress (sigma) to axial strain () in the ela

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a)

(i) Young's Modulus (E) is a measure of the stiffness or elastic modulus of a material. It is defined as the ratio of tensile or compressive stress ($\sigma$) to axial strain ($\epsilon$) in the elastic deformation region.

$$E = \frac{\sigma}{\epsilon} = \frac{F/A}{\Delta L/L_0}$$

Where:

• $F$ is the applied force.
• $A$ is the cross-sectional area.
• $\Delta L$ is the change in length.
• $L_0$ is the original length. Its SI unit is Pascals (Pa) or Newtons per square meter ($\text{N/m}^2$).

(ii) Young's modulus directly affects the stiffness of a material. A higher Young's modulus indicates a stiffer material, meaning it requires a greater amount of stress to produce a given amount of strain (deformation). Conversely, a material with a lower Young's modulus is less stiff and will deform more easily under the same stress.