Every material obeys the Hook’s law within its
- AElastic Limit
- BPlastic Limit
- CLimit of ProportionalityCorrect
- DDeflection limit
Solution
Concept
Hooke's law (stress ∝ strain) holds only up to the limit of proportionality.
Formula
σ = E × ε
Step-by-step solution
1. Hooke's law says stress is directly proportional to strain. 2. This linear relation holds only on the straight part of the stress-strain curve. 3. The straight part ends at the limit of proportionality. 4. So Hooke's law is obeyed within the limit of proportionality.
Explanation
Hooke's law means stress and strain are linearly related. This is true only up to the limit of proportionality. Between this limit and the elastic limit, the material is still elastic but not linear.
Why the other options are wrong
A: Up to the elastic limit the material recovers its shape, but the relation may not be linear. B: In the plastic range Hooke's law does not apply. D: Deflection limit is a serviceability limit, not a material property.
Shortcut
Hooke's law means linear, and linear means limit of proportionality.
Common mistake
Treating elastic limit and limit of proportionality as the same point.
Correct answer: C) Limit of Proportionality