The warmer of the two.
Three switches outside a windowless room.
Feel the two bulbs that are not lit.
Then turn the second switch off and enter the room after half a minute.
You are outside the room and the door is closed.
Each light is connected to one of three switches outside of the room.
Each bulb is switched off at present.
A windowless room contains three identical light fixtures each containing an identical light bulb or light globe.
Turn the first two switches on and leave them on for 2 minutes.
Three switches outside a windowless room are connected to three light bulbs inside the room.
Then switch on the second switch and enter the room.
Switch on the first switch leave it for a minute and then switch it off again.
Then switch on the second switch and enter the room.
How can you determine which switch is connected to which bulb if you are only allowed to enter the room once.