Question

Puzzle 4: You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?​

Answer 1

Explanation:

1st bulb: switch it on, after few seconds turn it off.

2nd bulb: leave it switched on.

3rd bulb: do nothing.

open the door, observe, touch, see:

1st bulb: you must feel warm when you touch it.

2nd bulb: must be glowing as it's switched on.

3rd bulb: you gonna feel nothing, as it's left undone.

Answer 2

Answer:

Switch on switches 1 & 2, wait a moment and switch off number 2. Enter the room. Whichever bulb is on is wired to switch 1, whichever is off and hot is wired to switch number 2, and the third is wired to switch 3. Obviously any combination would work.