A wire 3 m in length and area of cross section 3×10-7m2 originally at 300C is now kept at a low temperature of -1700C and is stretched by hanging a weight of 20 kg at one end. The change in length of the wire is [Y = 2×1011N/m2 g = 10 m/s2 and α = 1.2×10-5/C  0]