Question

Permanent dimension changes due to loading is termed as:

• A. Strain
• B. Extent
• C. Creep
• D. Ambit

Hint:

Creep is significant in materials like concrete and metals at high temperatures or under long-term loading.

Answer 1

The Correct Option is C

Step 1: Understand the term “permanent deformation.”
Permanent deformation refers to deformation that remains even after the removal of load.
Step 2: Definition of creep.
Creep is the time-dependent permanent deformation of a material when subjected to a constant load or stress over a long period of time.
Step 3: Analyze the options.
(A) Strain: Strain is a general measure of deformation and can be elastic or plastic, not necessarily permanent.
(B) Extent: Not a standard term used in strength of materials.
(C) Creep: Correct, as it represents permanent dimensional change under sustained loading.
(D) Ambit: Not related to deformation mechanics.
Step 4: Conclusion.
Therefore, permanent dimension change due to loading is called creep.

Answer 2

Another way to identify the correct term is to consider what field each option's word actually belongs to, and check whether that field concerns permanent deformation under sustained load at all.

1. Strain: Strain is simply the general, instantaneous measure of deformation (change in length over original length) that appears the moment any load is applied, whether or not the material later returns to its original shape; it says nothing by itself about whether the deformation is permanent or time-dependent, so it is too generic a term to describe this specific phenomenon.
2. Extent: This is an everyday English word meaning the size or range of something; it has no specific, defined meaning within mechanics of materials or structural engineering, and cannot be the technical term being asked for here.
3. Creep: This is a specific, well-defined mechanics-of-materials term for the slow, permanent increase in deformation that accumulates in a material held under a constant load over an extended period of time, even though the stress itself never changes. This description matches "permanent dimension changes due to loading" exactly.
4. Ambit: Like "extent," this is a general English word (meaning scope or range) rather than an engineering term, and has no established meaning in the context of material deformation.

Ruling out the two words that are not engineering terms at all, and the one that only describes deformation in general without implying permanence over time, leaves only the specific technical term for slow, time-dependent permanent deformation.

Therefore, the correct answer is creep.