Two rods, one of iron and another of aluminium of equal length and equal cross-sections are connected with each other. The free end of the iron rod is kept at 100" "^(@)C and the free end of aluminium rod is kept at 0" "^(@)C. If thermal conductivity of aluminium is four times that of iron, find the temperature of their contact surface in the thermal steady state.

Two rods, one of iron and another of aluminium of equal length and equ

1.	Two rods, one of iron and another of aluminium of equal length and equal cross-sections are connected with each other. The free end of the iron rod is kept at 100" "^(@)C and the free end of aluminium rod is kept at 0" "^(@)C. If thermal conductivity of aluminium is four times that of iron, find the temperature of their contact surface in the thermal steady state.
Answer» Solution :`((DQ)/(dt))_(Fe)=((dQ)/(dt))_(Al)` `:.(KA[100-T_(x)])/(L)=(4KA[T_(x)-0])/(L)` `:.100-T_(x)=4T_(x)` `:.5T_(x)=100` `:.T_(x)=20" "^(@)C`