The length of steel rod is 5 cm longer than the copper rod at all temperatures. The length of the steel and copper rod is respectively (Coefficient of linear expansion for steel and copper is respectively 1.1 \times 10^{-5} /{ }^{\circ} \mathrm{C} and 1.7 \times 10^{-5} /{ }^{\circ} \mathrm{C} )