Two long ,thin,solid cylinders are identical in size, by they are made of different substances with

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:-

substances