The phenomenon of slow extension of a material, increasing with time under a constant load, is called:
Try it first: pick an option, then read the explanation.
Asked in SSC JE 03/03/2017 (Morning)
Detailed Explanation
Some deformations happen at once when a load is applied; others keep growing with time even though the load does not change.
Why “Creeping” Is Correct
The gradual increase of strain with time under a constant, sustained load is called creep. It is important for concrete (long-term deflection) and for metals at high temperature. Yielding, by contrast, is a large increase in strain at almost constant stress that happens when the yield point is reached — it is not a slow, time-dependent process.
Disputed answer: the printed key gives (c) ‘yielding’, reading the wording as ‘having no constant load’. The standard definition of slow extension increasing with time is creep, so we give (a).
Why the Other Options Are Wrong
- B. Breaking: Breaking is fracture, not slow extension.
- C. Yielding: Printed in the book's key, but yielding is not a slow time-dependent extension.
- D. None of these: Creep is listed as option (a).
Key Point
Creep: strain increasing with time under constant stress. Relaxation: stress falling with time at constant strain.
Key Concepts for Students
- Concrete creep can be 1–3 times the elastic strain.
- Creep increases deflection of beams over the years.
- Prestress loss is partly due to creep and relaxation.
Practice more: this is question 14 in Stress and Strain MCQs – Part 1. Try the whole set and check every answer instantly.