At 40 ° C, a brass wire of 1mm radius is hung from the ceiling. A...

At $40 ° C,$ 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 $40 ° C$ to $20 ° C$ 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 ${10}^{- 5}{/}^{°}C$ and ${10}^{11}N / {m}^{2},$ respectively; $g = 10m{s}^{- 2}$ )