Two wires, one made of copper and other of steel are joined end to end as shown in fig, The area of cross-section of copper wire is twice that of steel wire. They are placed under compressive force of magnitude F. The ratio of their lengths such that

 

change in length of both wires are same is
$\left({\mathrm{Y}}_{\mathrm{s}}=2\times {10}^{11}\mathrm{N}/{\mathrm{m}}^2\text{ and }{\mathrm{Y}}_{\mathrm{c}}=1\cdot 1\times {10}^{11}\mathrm{N}/{\mathrm{m}}^2\right)$