Question

The load versus elongation graph of four wires of same length and of the same material is shown in figure. The thinnest wire is represented by the line :

• A. $OA$
• B. $OB$
• C. $OC$
• D. $OD$

Answer 1

The correct option is A $OA$

$Y=\frac{F\times l}{A\times \Delta l}$ or $\frac{F\left(load\right)}{\Delta l\left(elongation\right)}=\frac{YA}{l}$

or slope $\propto A$

or slope $\propto r^2$

For thinnest wire slope is minimum.

ie, wire $OA$ is thinnest.