Q. Two rods, one of aluminium and the other made of steel ,having initial length $l_1 + l_2$. are connected together to form a single rod of length $l_1+l_2$. The coefficients of linear expansion for aluminium and steel are $\alpha_a$ and $\alpha_s$ respectively. if the lenghth of each rod increases by the same amount when their temperature are raised by $t^{\circ}C,$ then find the ratio $\frac{l_1}{l_1+l_2}$
IIT JEEIIT JEE 2003Thermodynamics
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