In the above solution, we assumed the temperature at any cross section of the wall normal to the x direction to be isothermal. We could also solve this problem by going to the other extreme and assuming the surfaces parallel to the x-direction to be adiabatic. The thermal resistance network in this case will be as shown in Figure. By following the approach outlined above, the total thermal resistance in this case is determined to be Rtotal=6.97C/W, which is very close to the value 6.85C/W obtained before. Thus either approach would give roughly the same result in this case. This example demonstrates that either approach can be used in practice to obtain satisfactory results. In the above solution, we assumed the temperature at any cross section of the wall normal to the x direction to be isothermal. We could also solve this problem by going to the other extreme and assuming the surfaces parallel to the x-direction to be adiabatic. The thermal resistance network in this case will be as shown in Figure. By following the approach outlined above, the total thermal resistance in this case is determined to be Rtotal=6.97C/W, which is very close to the value 6.85C/W obtained before. Thus either approach would give roughly the same result in this case. This example demonstrates that either approach can be used in practice to obtain satisfactory results