Three conductors of same length having thermal conductivity k_1, k_2 and k_3 are connected as shown in figure. Area of cross sections of 1^st and…

Three conductors of same length having thermal conductivity $\displaystyle \mathrm{k}_1, \mathrm{k}_2$ and $\displaystyle \mathrm{k}_3$ are connected as shown in figure. Area of cross sections of $\displaystyle 1^{\text {st }}$ and $\displaystyle 2^{\text {nd }}$ conductor are same and for $\displaystyle 3^{\text {rd }}$ conductor it is double of the $\displaystyle 1^{\text {st }}$ conductor. The temperatures are given in the figure. In steady state condition, the value of $\displaystyle \theta$ is $\displaystyle \_\_\_\_$ °C. (Given : $\displaystyle \mathrm{k}_1=60 \mathrm{Js}^{-1} \mathrm{~m}^{-1} \mathrm{~K}^{-1}, \mathrm{k}_2=120 \mathrm{Js}^{-1} \mathrm{~m}^{-1} \mathrm{~K}^{-1}, \mathrm{k}_3=135 \mathrm{Js}^{-1} \mathrm{~m}^{-1} \mathrm{~K}^{-1}$ )