A thin rod of negligible mass and area of cross-section 2∗10−5m2, suspended vertically from one end, has a length of 0.5 m at 200∘C. The rod is cooled to 0∘C, but length is kept same by attaching a mass at the lower end. The value of this mass is (Young's modulus =1011N/m2, Coefficient of linear expansion 10−5K−1).