Post:
You have three switches in one room and a single light bulb in another room. You are allowed to visit the room with the light bulb only once. How do you figure out which switch controls the bulb? Write your answer in the comments before looking at other answers.
Comment:
If this were an interview question, the correct response would be "Do you have any relevant questions for me? Because have a long list of things that more deserving of my precious time than to think about this!
Only works if it’s an incandescent light, but…
Flip one switch. Wait a few minutes. Flip it off.
Flip the second switch and go into the room.
If the light is on, it’s the switch you flipped most recently. If the light is off but warm, it was the first switch. If it’s off and cold, it’s the switch you didn’t touch.