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 $$B=1.1 \times 10^{11} \mathrm{~Nm}^{-2}$$).
5 g of ice at $$-30^{\circ} \mathrm{C}$$ and 20 g of water at $$35^{\circ} \mathrm{C}$$ are mixed together in a calorimeter. The final temperature of the mixture is (Neglect heat capacity of the calorimeter, specific heat capacity of ice $$=0.5 \mathrm{cal} \mathrm{g}^{-1}{ }^{\circ} \mathrm{C}^{-1}$$ and latent heat of fusion of ice $$=80 \mathrm{cal} \mathrm{g}^{-1}$$ and specific heat. capacity of water $$=1 \mathrm{cal} \mathrm{g}^{-1}{ }^{\circ} \mathrm{C}^{-1}$$)
A hydraulic lift is shown in the figure. The movable pistons $$A, B$$ and $$C$$ are of radius $$10 \mathrm{~cm}, 100 \mathrm{~m}$$ and 5 cm respectively. If a body of mass 2 kg is placed on piston $$A$$, the maximum masses that can be lifted by piston $$B$$ and $$C$$ are respectively.
An iron sphere having diameter $$D$$ and mass $$M$$ is immersed in hot water so that the temperature of the sphere increases by $$\delta T$$. If $$\alpha$$ is the coefficient of linear expansion of the iron then the change in the surface area of the sphere is