Woww! Finally, a scientific explanation for the puzzle! You didn’t just solve it, you brought physics into the game too! Brilliant answer!Well light emits photons it has to cross the band gap from valence band to reach the conduction band to produce energy since it will consume heat to get in the excited state , leaving the switch 1 on for some time to see if it controls the bulb , after switching it off and switching of the second bulb if it glows without some warmth 2nd controls otherwise the third one is answer.
