Steel wire has a length of 2m and cross-sectional area of $1mm^2$. When 20 N force is applied to the wiren its length is increased by $2\times 10^{-4}m$. What is the Young's modulus for steel?

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

$2.25 \times 10^{11} \mathrm{~N}-\mathrm{m}^{-2}$

$3.5 \times 10^{11} \mathrm{~N}-\mathrm{m}^{-2}$

$2 \times 10^{11} \mathrm{~N}-\mathrm{m}^{-2}$