Two wires $$A$$ and $$B$$ of same cross-section are connected end to end. When same tension is created in both wires, the elongation in $$B$$ wire is twice the elongation in $$A$$ wire. If $$L_A$$ and $$L_B$$ are the initial lengths of the wires $$A$$ and $$B$$ respectively, then (Young's modulus of material of wire $$A=2 \times 10^{11} \mathrm{~Nm}^{-2}$$ and Young's modulus of material of wire $$B=1.1 \times 10^{11} \mathrm{~Nm}^{-2}$$).

Same tension is applied to the following four wires made of same material. The elongation is longest in

Young's modulus of a wire is $$2 \times 10^{11} \mathrm{Nm}^{-2}$$. If an external stretching force of $$2 \times 10^{11} \mathrm{~N}$$ is applied to a wire of length $$L$$. The final length of the wire is (cross-section = unity)