# Question #161a9

Young's modulus ($Y$) is expressed as $\frac{\frac{F}{A}}{\frac{\delta l}{l}}$ (where, $F$ is the force, $A$ is the cross sectional area $\delta l$ is change in length and $l$ is the original length)
Given, $Y = 2 \cdot {10}^{-} 11 , A = \frac{1}{10000} , \frac{\delta l}{l} = 1$
So, $F = 2 \cdot {10}^{-} 15 N$