At 40^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^oC to 20^oC 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
/^oC and 10¹¹ N/m
²
, respectively; g=
10 ms^–2
)