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At \( 40^{\circ} \mathrm{C} \), a brass wire of \( 1 \mathrm{~mm} \) radius is hung from the ceiling. A small mass, \( M \) is hung from the free end of
\( \mathrm{P} \) the wire. When the wire is cooled down from \( 40^{\circ} \mathrm{C} \) to

W) \( 20^{\circ} \mathrm{C} \) it regains its original length of \( 0.2 \mathrm{~m} \). The value of \( \mathrm{M} \) is close to :
(Coefficient of linear expansion and Young' s modulus of brass are \( 10^{-5} /{ }^{\circ} \mathrm{C} \) and \( 10^{11} \mathrm{~N} / \mathrm{m}^{2} \), respectively; \( \mathrm{g}=10 \mathrm{~ms}^{-2} \) )
[JEE Main-2019 (April)]
(1) \( 1.5 \mathrm{~kg} \)
(2) \( 9 \mathrm{~kg} \)
(3) \( 0.9 \mathrm{~kg} \)
(4) \( 0.5 \mathrm{~kg} \)
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