The temperature of a wire is doubled. The Young's modulus of elasticity

If the ratio of lengths, radii and Young's Moduli of steel and brass wires in the figure are $$\mathrm{a}, \mathrm{b}$$ and $$\mathrm{c}$$ respectively, then the corresponding ratio of increase in their lengths would be

Two wire of same material having radius in ratio 2 : 1 and lengths in ratio 1: 2. If same force is applied on them, then ratio of their change in length will be

Two wires are made of the same material and have the same volume. The first wire has cross-sectional area $$A$$ and the second wire has cross-sectional area $$3 A$$. If the length of the first wire is increased by $$\Delta l$$ on applying a force $$F$$, how much force is needed to stretch the second wire by the same amount?