If the length of a string is $P$ when the tension in it is 6 N and its length is $Q$ when the original length of the string is

A steel wire of length 3 m and a copper wire of length 2.2 m are connected end to end. When the combination is stretched by a force, the net elongation is 1.05 mm . If the area of cross-section of each wire is $6 \mathrm{~mm}^2$, then the load applied is (Young's moduli of steel and copper are respectively $2 \times 10^{11} \mathrm{Nm}^{-2}$ and $1.1 \times 10^{11} \mathrm{Nm}^{-2}$ )

A wire of length 40 cm is stretched by 0.1 cm . The strain on the wire is