Which of the following terms is a measure of the stiffness of a material?

Young's Modulus of Elasticity is the correct term that measures the stiffness of a material. It is defined as the ratio of stress (force per unit area) to strain (deformation) in the elastic region of the material's stress-strain curve. This modulus provides insight into how much a material will deform under a given load, allowing engineers to predict how materials will behave under various loading conditions. A higher Young's Modulus indicates that a material is stiffer, meaning it will deform less under a given load compared to a material with a lower Young's Modulus.

In contrast, tensile strength refers to the maximum amount of tensile stress a material can withstand before failure, but it does not provide information about stiffness. The elastic limit describes the maximum stress that a material can withstand without permanent deformation, while elasticity is a general term that refers to the ability of a material to return to its original shape after being deformed. Although these concepts are related to material properties, they do not specifically quantify stiffness, which is the primary focus when discussing Young's Modulus of Elasticity.