Let's suppose you have a big capacitor (1 farad or so) charged up, and you connect an LED across it. It will keep it glowing for several minutes at least. While this is going on, does the circuit overall (LED, cap, wire...) lose an infinestimately small amount of weight due to the photons leaving the LED?
Is the loss in weight because some of the electrons stored in the cap were actually *converted* to photons, or is the photon production explained by energy being directly converted to mass (E=MC^2)? Thanks.