Simple Stress and Strain MCQ with answer and solution

Concept

Beyond the limit of proportionality, strain grows faster than stress.

Step-by-step solution

1. Up to the limit of proportionality, stress is proportional to strain, so the curve is a straight line. 2. Between the proportional limit and the elastic limit, the curve starts to bend. 3. In this zone, a small rise in stress gives a larger rise in strain. 4. So, as the elastic limit is reached, tensile strain increases more rapidly.

Explanation

Near the elastic limit the stress-strain curve becomes curved. Strain then increases faster than stress. So strain increases more rapidly.

Why the other options are wrong

B: Strain does not decrease under increasing tensile load. C: Strain is proportional to stress only up to the limit of proportionality, not near the elastic limit. D: Strain never decreases in proportion to stress during loading.

Shortcut

After the straight-line part, strain runs ahead of stress.

Common mistake

Choosing C by assuming Hooke's law holds right up to the elastic limit.