A wire of cross-sectional area $3 \mathrm{~mm}^2$ is first stretched between two fixed points at a temperature of $20^{\circ} \mathrm{C}$. Determine the tension when the temperature falls to $10^{\circ} \mathrm{C}$. Coefficient of linear expansion $\alpha=10^{-5}{ }^{\circ} \mathrm{C} \mathrm{C}^{-1}$ and $Y=2 \times 10^{11} \mathrm{~N} / \mathrm{m}^2$