When the load applied to a wire is increased from 5 kg wt to 8 kg wt . The elongation of the wire increases from 1 mm to 1.8 mm . The work done during the elongation of the wire is (acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

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 $$B=1.1 \times 10^{11} \mathrm{~Nm}^{-2}$$).