question_answer

At \[40{}^\text{o}C,\]a brass wire of 1 mm 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 \[40{}^\text{o}C\]to \[20{}^\text{o}C\] it regains its original length of 0.2 m. The value of M is close to : (Coefficient of linear expansion and Young's modulus of brass are \[{{10}^{5}}/{}^\text{o}C\]and \[{{10}^{11}}N/{{m}^{2}},\] respectively; \[g=10\,m{{s}^{-2}}\])                                         [JEE Main Held on 12-4-2019 Morning]

A) \[1.5\,kg\]                    

B) \[9\text{ }kg\]

C) \[0.9\text{ }kg\]                       

D) \[0.5\text{ }kg\]