This should be a simple question but I'm really not sure what's the answer. Let's make a thought experiment: I have a radio transmitter and a radio receiver, operating at wavelength 10 meters. I put them in a sealed copper cube that is only 1x1x1 meter. Will the two radios be able to communicate or not? What if the box was superconductive? My reasoning is that 1. The two radios can only communicate via photons 2. A 10m photon cannot fit in the box 3. Thus communication is impossible (at the specified frequency) Some of my friends say that the two antennas will affect each other, like a transformer, but we have not come to a definite conclusion. Alternative question, what if the box was 1x1x100 meters, with the receiver placed at the far end?