If there is EM radiation, will there always be a heat exchange between the wave and its surroundings? If you have an extremely energy-efficient light bulb that converts ALL the energy it receives into visible light, will it still heat up the glass bulb?
The origin of this question is a puzzle:
You are in a basement. You cannot see the above floor. You have three light switches in basement and three light bulbs in the above floor, but you do not know which switch controls which bulb. Modify the switches in any way, but you can only go to check the bulbs once. When you check the bulbs, you must immediately know which switch controls which bulb.
The solution is to turn on the switch for a long time to heat up the corresponding bulb, then turn on a second bulb. The light bulbs will be ON and HOT, ON and COLD, and OFF. This info can be used to find the corresponding switches.
This is true with incandescent light bulbs that are known for being energy inefficient, converting much of the energy it receives in to heat instead of light. If I have an incredibly energy-efficient light bulb, will this still work?