A stell wire of cross-sectional area `0.5mm^2` is held between teo fixed supports. If the wire is just taut at `20^C`, determine the tension when the temperature falls to `0^C`. Coefficient of linear expansion of steel is `1.2 xx 10^(-5) 0^C(-1)` and its Young's modulus is `2.0 xx 10^11 N m^(-2).