Lets say a hot object is at 500K and placed in a chamber with wall temperature of 300K. The surrounding air in the chamber is 320K. So what is the mode of heat transfer for the hot objection? There is convection and radiation. so the heat transfer rate, q = q(conv) + q(rad), right? Convection is between object and surrounding air. But what about radiation? Is it between the object and the chamber walls or is it between the object and the surrounding air? Depending on which is chosen, the q(rad) will varies since q(rad) depends on the temperature difference of the 2 body. Can anyone help me out? I am confused on using 500K and 300K to calculate q(rad) or 500K and 320K.