A Level Physics Practice Exam

What characterizes the stress-strain graph for a ductile material?

1. It shows no yield point

2. It displays a linear relationship

3. It shows a potential break without prior deformation

4. It has a significant yield point followed by strain hardening

The correct answer is: It has a significant yield point followed by strain hardening

The stress-strain graph for a ductile material is characterized by a significant yield point followed by strain hardening. This behavior is indicative of how ductile materials respond to stress when they are deformed. Initially, ductile materials exhibit elastic behavior, where the stress is proportional to strain, and they return to their original shape upon release of the load. As the stress increases, a point is reached known as the yield point, where the material begins to deform plastically. After yielding, further strain occurs with an increase in stress, which is a sign of strain hardening. During this phase, the material becomes stronger and more resistant to deformation due to the rearrangement of its internal structure. In contrast to other materials that may fracture or show no yielding, ductile materials typically show a pronounced yield point followed by this hardening behavior, allowing them to undergo larger permanent deformations before eventual failure. Thus, the answer accurately reflects the typical characteristics of a ductile material's response to tensile stress.