Question 38 of 126

At $40^{\circ}C,$ a brass wire of $1mm$ radius is hung from the ceiling. A small mass, $M$ is hung from the free end of the wire. When the wire is cooled down from $40^{\circ}C$ to $20^{\circ}C$ it regains its original length of $0.2m.$ The value of $M$ is close to:
(Coefficient of linear expansion and Young’s modulus of brass are ${10}^{-5}{/}^{^{\circ}}C$ and ${10}^{11}N/{m}^{2},$ respectively; $g=10m{s}^{-2}$ )