As shown in the figure, in an experiment to determine Young's...

Given here, $L = 62 . 8cm\text{and}d = 4mm$.

From the given graph, we can see that extension in wire is linearly dependent on force applied. Slope of the curve is $\tan 45 ° = 1$.

So, $F = \DeltaL$

Young's modulus is given by $Y = \dfrac{FL}{A\DeltaL}$, where, $A$ is area of wire.

$⇒ Y = \dfrac{L}{A}$

$⇒ Y = \dfrac{62 . 8 \times {10}^{- 2}}{\pi{\left(2 \times {10}^{- 3}\right)}^{2}}$

$⇒ Y = 5 \times {10}^{4}N{m}^{- 2}$