A brass wire 2 m long at 27oC is held taut with negligible tension between two rigid supports. If the wire is cooled to a temperature of -33oC, then the tension developed in the wire, its diameter being mm, will be (coefficient of linear expansion of brass = 2.0 x 10-5/oC and Young's modulus of brass = 0.91 x 1011 Pa)

Thermal stress that is produced in an elastic wire is  Yα θ per unit area, where Y is Young's modulus, a coefficient of linear expansion and θ change of temperature.Thus, tension developed in the wire isT = Thermal stress x area of cross section=Yα×(ΔT)πr2N=0.91×1011×2×10−5×[27−(−33)]π×1×10−6N=0.91×2×6×3.14×10N=34.4×10N=0.34kN