JEE Main 2019 — Mechanical Properties of Solids Question with Solution

In an experiment, brass and steel wires of length $1\mathrm{ }\mathrm{m}$ each with areas of cross section $1\mathrm{ }\mathrm{m}{\mathrm{m}}^2$ are used. The wires are connected in series and one end of the combined wire is connected to a rigid support and other end is subjected to elongation. The stress required to produce a net elongation of $0.2\mathrm{ }\mathrm{m}\mathrm{m}$ is,
[Given, the Young's Modulus for steel and brass are, respectively, $120\times {10}^9\mathrm{ }\mathrm{N}/{\mathrm{m}}^2$ and $60\times {10}^9\mathrm{ }\mathrm{N}/{\mathrm{m}}^2$ ]