Two rectangular blocks, having identical dimensions, can be arranged either in configuration $I$ or

Question

Two rectangular blocks, having identical dimensions, can be arranged either in configuration $I$ or in configuration II as shown in the figure. One of the blocks has thermal conductivity k and the other 2 k . The temperature difference between the ends along the x -axis is the same in both the configurations. It takes 9s to transport a certain amount of heat from the hot end to the cold end in the configuration I. The time to transport the same amount of heat in the configuration II is :-

Professor PC Thomas Classes · Answer

$\Rightarrow \frac{\Delta T}{3 R} t_1=\frac{3 \Delta T}{2 R} t_2 \Rightarrow t_2=\frac{2}{9} t_1=2 \mathrm{sec}$.