Question

A steel wire $10m$ long and ${10}^{-5}{m}^2$ in cross-sectional area elongates by $0.01m$ under a tension of $2500N$. Young's modules for steel from the data is computed as

• A. $2.5\times {10}^{7}N{m}^{-2}$
• B. $2.5\times {10}^{9}N{m}^{-2}$
• C. $2.5\times {10}^{11}N{m}^{-2}$
• D. None of these

Answer 1

The correct option is C $2.5\times {10}^{11}N{m}^{-2}$

Young's Modulus is given by:

$Y=\frac{FL}{A\Delta L}$

$=\frac{2500\times 10}{{10}^{-5}\times 0.01}$

$=2.5\times {10}^{11}N{m}^{-2}$