Two uniform metal rods of length L₁ and L₂ and their linear coefficients of expansion α₁ and α₂ respectively, are connected to form a single rod of length $\left({\mathrm{L}}_1+{\mathrm{L}}_2\right).$. When the temperature of combined rod is raised by $"{\mathrm{t}}^0\mathrm{C}"$,the length of each rod increased by the same amount then $\left(\frac{{\mathrm{\alpha }}_2}{{\mathrm{\alpha }}_1+{\mathrm{\alpha }}_2}\right) \mathrm{is}$