Question: What is the definition of yield strength?

Options:

1. The maximum stress a material can withstand
2. The stress at which a material begins to deform plastically
3. The stress at which a material breaks
4. The stress at which a material is fully elastic

Correct Answer: The stress at which a material begins to deform plastically

Solution:

Yield strength is defined as the stress at which a material begins to deform plastically, meaning it will not return to its original shape.