1. The problem statement, all variables and given/known data Prepairing for a test and this one came up that's confusing me. A spherical object, water cooled, with a diameter of 10 milimeters and ε = 0,9 is kept at 353 degrees Kelvin, when placed in a very large furnace where a vaccum is formed and which walls are kept at 673 degrees kelvin. What's the Transfered heat exchange (same as heat flux I think) by the furnace walls into the object? 2. Relevant equations q =A ε σ T4 q =A ε σ (Ts4 - To4) hr = A ε σ (Ts4 + To4)(Ts + To) Ts - Surface temperature To - object temperature 3. The attempt at a solution I know from the solution is 3,04 W. But I don't know how to get there. At first it seemed very straight forward since I'm given all the data to just replace the values in the formula. I've tried that but the value is always different from the solution. What confuses me is that what is asked is the transfered heat exchange from the walls to the object not the other way arround. Would really apreciate some help on this.