Question

In an experiment to determine the Young's modulus, steel wires of five different lengths $(1,2,3,4$ and $5m)$ but of same cross section $(2m{m}^2$ ) were taken and curves between extension and load were obtained. The slope (extension/load) of the curves were plotted with the wire length and the following graph is obtained. If the Young's modulus of given steel wires is $x\times 10^{11}N{m}^{-2}$, then the value of $x$ is ______

Answer 1

Answer: 2

Slope $=\frac{\Delta l/w}{L}=\frac{\Delta l/L}{w}=\frac{1}{YA}$
$\Rightarrow Y=\frac{1}{(\text{ slope })A}$
$Y=\frac{1}{2\times 10^{-6}\left(0.25\times 10^{-5}\right)}$
$Y=2\times 10^{11}N/m^2$