Question

The load versus elongation graph for four wires of the same material is shown in the figure. The thickest wire is represented by the line

• A. OD
• B. OC
• C. OB
• D. OA

Answer 1

Answer: (A)

OD

Answer 2

Young's modulus $Y = \frac{FL}{Al}$ ∴ $l \propto \frac{1}{A}$ (As Y, L and F are constant)

From the graph it is clear that for same load elongation is minimum for graph OD.

As elongation (l) is minimum therefore area of cross-section (1) is maximum.

So thickest wire is represented by OD.