Elasticity

A wire of length 0.5 m and area of cross-section $4 \times 10^{-6} \mathrm{~m}^2$ at a temperature of $100^{\circ} \mathrm{C}$ is suspended vertically by fixing its upper end to the ceiling. The wire is then cooled to $0^{\circ} \mathrm{C}$, but is prevented from contracting by attaching a mass at the lower end. If the mass of the wire is negligible, then the value of the mass attached to the wire is

[Young's modulus of material of the wire $=10^{11} \mathrm{Nm}^{-2}$, coefficient of linear expansion of the material of the wire $=10^{-5} \mathrm{~K}^{-1}$ and acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ ]