Which of the following is the correct pair?

The length of a metallic wire is $\ell_{1}$ when the tension in it is $T_{1}$. It is $\ell_{2}$ when the tension is $T_{2}$. The original length of the wire will be ...... .

Select the correct alternative$(s)$.

The load versus elongation graph for four wires of the same material is shown in the figure. The thickest wire is represented by the line

$A$ wire of length $l$ and cross-sectional area $A$ is stretched by a weight $Mg$ such that its length becomes double. What is the stress in the wire?

Wires $W_{1}$ and $W_{2}$ are made of the same material having a breaking stress of $1.25 \times 10^{9} \, N/m^{2}$. $W_{1}$ and $W_{2}$ have cross-sectional areas of $8 \times 10^{-7} \, m^{2}$ and $4 \times 10^{-7} \, m^{2}$,respectively. Masses of $20 \, kg$ and $10 \, kg$ hang from them as shown in the figure. The maximum mass $m$ that can be placed in the pan without breaking the wires is $..... \, kg$. (Use $g = 10 \, m/s^{2}$)