Goldilocks and the Three Light Bulbs

For all you brainiacs out there, heres a good one:

There is a room with a single light bulb inside of it. The door is completely sealed off and you are on the outside. The outer wall of this room has three light switches. Only one of them switches the light bulb on.

Your challenge is to identify which light bulb it is. You can fiddle with the switches for as long as you want uptil the time you want to open the door. When you open the door and step inside, only one of the switches can be on and you NEED to identify which switch is the real one.

PS: You don't lose if you walk in with a switch on and that isn't the one. You just need to be able to tell which button switches on the light bulb.


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ANSWER: Turn on switch #1 and wait half an hour. Switch it off and switch on #2 and immediately enter. If it is #2, you shall see the lightbulb on. If not, its either #1 or #3. To determine that, touch the light bulb. If its warm, it will be #1. If cold, #3.

*Blink*