How can the elastic limit be defined?

The elastic limit can be defined as the maximum stress that a material can withstand while still returning to its original shape once the stress is removed. This is critical in understanding material behavior because it delineates the boundary between elastic behavior, where the material deforms but fully recovers, and plastic behavior, where permanent deformation occurs.

In this context, the option that describes the maximum stress under tension that can be induced without failure accurately reflects the essence of the elastic limit. Materials that experience stress beyond this point enter a phase where they cannot fully recover their original shape, leading to permanent deformation.

The other options, while related to material properties, do not specifically capture the definition of the elastic limit. For instance, measuring elongation before failure pertains more to ductility and tensile strength rather than the threshold of elastic versus plastic deformation. Similarly, the minimum stress required for permanent deformation and maximum strain before failure delve into other aspects of material behavior without focusing on the specific definition of the elastic limit.