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 $60\times {10}^9\mathrm{ }\mathrm{N}/{\mathrm{m}}^2$ ]

• Correct answer
  A

  $8.0\times {10}^6\mathrm{ }\mathrm{N}/{\mathrm{m}}^2$
• B

  $1.2\times {10}^6\mathrm{ }\mathrm{N}/{\mathrm{m}}^2$
• C

  $0.2\times {10}^6\mathrm{ }\mathrm{N}/{\mathrm{m}}^2$
• D

  $1.8\times {10}^6\mathrm{ }\mathrm{N}/{\mathrm{m}}^2$

Hence, the correct answer is option: 'A'.