A Level Physics Practice Exam

What occurs between the ultimate tensile strength (UTS) and breaking point on a stress-strain graph?

1. The material hardens and becomes less ductile

2. The material extends and narrows until it breaks

3. The material retains constant strength

4. The material completely returns to its original shape

The correct answer is: The material extends and narrows until it breaks

The choice that indicates what occurs between the ultimate tensile strength (UTS) and the breaking point on a stress-strain graph is correct. After reaching the UTS, the material has experienced maximum stress and begins to undergo necking, which is where it extends significantly and narrows at a specific location. This necking process happens because the material cannot withstand any further increase in load without undergoing deformation. The region between UTS and the breaking point is characterized by this reduction in cross-sectional area leading up to fracture. This phase is vital in understanding material properties because it reflects the limitations in a material's ability to bear stress while maintaining its structural integrity. The changes happening during this time indicate the transition from a phase of maximum load-bearing capacity to eventual failure.