How is strain defined in relation to stress?

Strain is defined as the measure of deformation representing the displacement between particles in a material body that results from an applied stress. It quantifies how much a material deforms relative to its original length when subjected to an external load. In this context, deformity refers to changes in shape or dimensions caused by the stress applied to a material.

This concept directly connects to how materials respond when a force is applied; as stress increases, the material will experience strain, resulting in deformation. Therefore, the understanding of strain as a deformity contrast to the applied load emphasizes its role as an observable effect of the internal changes within the material structure.

By comprehending strain in this way, it becomes clear that it is inherently tied to the physical response of materials under stress rather than merely being an external force, an internal force, or a type of stress. Each of those other options fails to capture the essence of strain as a direct measure of deformation.