Two long ,thin,solid cylinders are identical in size, by they are made of different substances with two different thermal conductivities. The two cylinders are connected in series between a reservoir at temperature `T_("hot")` and a reservoir at temperature `T_("cold")`.The temperature at the boundary between the two cylinders is `T_("b")`. One can conclude that:-

Options

A. `T_(b)` is closer to `T_("hot")` than it is to `T_("cold")`.
B. `T_(b)` is closer to `T_("cold")` than it is to `T_("hot")`.
C. `T_(b)` is closer to the temp. of the reservoir that is in contact with the cylinder with the lower thermal conductivity.
D. `T_(b)` is closer to the temp. of the reservoir that is in contact with the cylinder with the higher thermal conductivity.

Answer

D

Explanation

For same rate of heat transfer the body having higher conductivity will have lower temperature difference. If cylinder with higher conductivity is connected with hot reservoir first then the function temperature `T_("b")`, will be closer to hot reservoir temperature.