Sol. From graphi
$$
\begin{aligned}
& \mathrm{F}=\Delta \mathrm{L} \\
& \mathrm{Y}=\frac{\mathrm{FL}}{\mathrm{~A} \Delta \mathrm{~L}} \\
& \mathrm{Y}=\frac{\mathrm{L}}{\mathrm{~A}} \\
& \mathrm{Y}=\frac{62.8 \times 10^{-2}}{\pi\left(2 \times 10^{-3}\right)^2} \\
& \mathrm{Y}=5 \times 10^4 \mathrm{~N} / \mathrm{m}^2
\end{aligned}
$$