3 Switches

Three switches outside a windowless room are connected to three light bulbs inside the room. How can you determine which switch is connected to which bulb if you are only allowed to enter the room once?

Originally posted by PureRWandB
Three switches outside a windowless room are connected to three light bulbs inside the room. How can you determine which switch is connected to which bulb if you are only allowed to enter the room once?

Originally posted by forkedknight
Are they LED's?

This puzzle isn't going to make sense in 20 years 🙂

Originally posted by PureRWandB
Three switches outside a windowless room are connected to three light bulbs inside the room. How can you determine which switch is connected to which bulb if you are only allowed to enter the room once?

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I guess it would be possible to trace each wire with your hands by walking through the window with a hand tracing two of the wires and using the rules of elimination to figure out the other light bulb and switch.

Originally posted by Jono3000
I guess it would be possible to trace each wire with your hands by walking through the window with a hand tracing two of the wires and using the rules of elimination to figure out the other light bulb and switch.

Turn one switch on After a half hour turn it off and turn another on. Then go in the room. One bulb will be on, corresponding to the switch you just turned on. There will be two bulbs turned off; but one of them will be warm, corresponding to the switch you turned on for a half hour. The cold one will correspond to the switch that was never turned on.

Originally posted by AThousandYoung
nope, incandescent bulbs

Originally posted by forkedknight
Now solve for LED's

Originally posted by forkedknight
Now solve for LED's

LED

Turn the left switch on and leave it for a few days.

When you come back turn the middle switch on

Enter room

Dim light belongs to the left switch

Bright one to the middle etc

Enter the room, replace the leds with bulbs of 3 known different resistances, noting the positions

Exit the room and take apart the switches, then use a multimeter to determine which switch is connected to which bulb.

Originally posted by iamatiger
Enter the room, replace the leds with bulbs of 3 known different resistances, noting the positions

Exit the room and take apart the switches, then use a multimeter to determine which switch is connected to which bulb.

Find someone else to stand outside the room and turn each switch on and off in an agreed order while you watch the bulbs from inside the room.

Put one switch on. Wait 5 minutes and put another switch on.

The bulb that is out will be the switch that is off, the bulb that is hot will
be the first switch you put on and the bulb that is cooler will be the last
switch put on.