Two rods, one of aluminium and the other of steel, having initial lengths ' $\mathrm{L}_1$ ' and ' $\mathrm{L}_2$ ' are connected together to form a single rod of length $\left(\mathrm{L}_1+\mathrm{L}_2\right)$. The coefficients of linear expansion of aluminium and steel are ' $\alpha_1$ ' and ' $\alpha_2$ ' respectively. If the length of each rod increases by the same amount, when their temperatures are raised by ${ }^{\prime} t^{\circ} \mathrm{C}$, then the ratio $\frac{\mathrm{L}_1}{\mathrm{~L}_1+\mathrm{L}_2}$ will be

• A

  $\frac{\alpha_2}{\alpha_1}$
• B

  $\frac{\alpha_1}{\alpha_2}$
• Correct answer
  C

  $\frac{\alpha_2}{(\alpha_1+\alpha_2)}$
• D

  $\frac{\alpha_1}{(\alpha_1+\alpha_2)}$

Hence, the correct answer is option: 'C'.