Question

In an experiment to determine the Young’s modulus, steel wires of five different lengths (1, 2, 3, 4 and 5 m) but of same cross section (2 mm2) 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 × 1011 Nm–2, then the value of x is ______.

Fig. Graph

Answer 1

The correct answer is 2
$Y = \frac{F×l}{A×Δl}$
$=\frac{1}{A}× \frac{Wire\ length}{\frac{Extension}{load}}$
$Y =\frac{1}{A}×(\frac{1}{0.25×10^{-5}})$
$Y = 10^{11}×2$
⇒ x = 2