Strain in a material is defined as which of the following?

Strain in a material is fundamentally defined as the measure of deformation resulting from an applied stress. Specifically, it describes how much a material deforms relative to its original length when subjected to an external load. This is calculated as the change in length (the difference between the new length and the original length) divided by the original length of the material.

Choosing the correct definition of strain underscores the importance of understanding how materials behave under stress in various contexts, such as engineering and materials science. The ratio provides a dimensionless quantity that indicates how much the material has been stretched or compressed compared to its original size, allowing for comparisons across different materials and designs.

The other definitions do not accurately encapsulate the concept of strain. For example, material density changes or mass per unit volume pertain to other physical properties rather than deformation characteristics. Understanding the distinction is crucial for applying principles of mechanics and ensuring that materials are used effectively in design and technology applications.