Answer: 0.5 mm.
- A 0.25 mm
- B 0.5 mm
- C 1 mm
- D 2 mm
Correct answer: B. 0.5 mm
Explanation: ΔL = FL/(AY), A ∝ r². New ΔL = old·(2L/L)·(A/4A) = old·(2/4) = 0.5 mm.
A typical stress-strain curve: the initial straight line (Hooke's Law region, slope = Young's modulus) ends at the elastic limit; beyond the yield point, deformation becomes permanent, peaking at the ultimate tensile strength before the wire finally fractures.
Concept context
Stress, strain, Hookes law, and the elastic moduli that describe how solids deform and recover under load.