[![enter image description here][1]][1] [1]: https://i.sstatic.net/CZUFl.png I am curious about making the inner walls of this blackbody perfectly reflecting instead of perfectly absorbing. 1.If I keep on giving in incident radiation,the photon density inside will increase,will it result in any interesting observation? 2.There will still be a non zero radiation escaping out through the inlet,so after giving in a large amount of radiation,will it work like a torch,with radiation escaping the closed system over time?