Forgive me if this has been posted and if you know the answer please let fellow members have a chance.

You have two rooms, in one room (A) there are three light switches in the other room (B) there is a single light bulb. ONLY one switch is connected to the bulb, the other two go no where.

You can position the switches in any order you want all on, all off, some on, some off etc. You THEN can enter room B where the light is to see the bulb. The challenge is tell me which switch operates the bulb? You have to do so with 100% accuracy. It is a foolproof solution.

Remember, only enter the room once. No tools are required, etc. You can not see one room while in the other. I think I have given all the criteria. Have fun.

Scott

Sorry Scott, we've already done this one in this section. It's a great puzzle though. Check the archives of "Puzzle me this".

There have also been a few other light bulb puzzles that have come about after this one including a crazy one by Nir Dahan about 100 convicted men, a lightbulb and an empty room.

Here's a similair one that I don't think has been done (in here) yet:

Nine wires go from upstairs to downstairs. At both ends all nine wires come through a hole in the wall. All the wires look the same. An electrician is downstairs with a device for testing connections. How many trips up and down the stairs does he have to make before he knows where all nine wires start and end?

Electricians actually leave an electric drill on and plugged in so that they don't have to run up and down; they can hear when it's on.

Interesting fact, Opus. The guy in the puzzle left his drill at home and the wires aren't connected to any mains supply anyhow...

Well, he is obviously dealing with a non-union job, and now it is really gonna cost to correct it.