Homework Statement
A furnace wall is made up of 3 layers:
1. 4mm layer of material with thermal conductivity of 52 W/m.K
2. 2mm layer of material with thermal conductivity of 20 W/m.K
3. 1mm layer of material with thermal conductivity of 3 W/m.K
There is an air gap between layers 1&2 with a...