Project ForgeHeat Transfer
Conduction
GATE 2016
Medium
Steady one-dimensional heat conduction takes place across faces 1 and 3 of a composite slab (A then B in perfect contact). kA=20 W/m·K (0.1 m thick), kB=100 W/m·K (0.3 m thick). T1=130°C, T3=30°C. The interface temperature T2 (in °C) is __________.
67.5 °C(± 0.5 accepted)
Explanation
Same heat flux through both slabs: kA(T1-T2)/LA = kB(T2-T3)/LB → 20(130-T2)/0.1 = 100(T2-30)/0.3 → 200(130-T2) = 333.33(T2-30) → 26000-200T2 = 333.33T2-10000 → T2 = 36000/533.33 ≈ 67.5°C.
Source: GATE ME 2016 Set-3 (2016)
This question is part of a 15-day revision cycle — sign in and Project Forge will bring it back the day before you'd forget it.