# Puzzles & Games Do you see the light - Solved

Discussion in 'Puzzles & Games' started by kiwirobin, Feb 1, 2005.

A light bulb is hanging in a room. Outside of the room there are three switches, of which only one is connected to the lamp. In the starting situation, all switches are 'off' and the bulb is not lit.

The Question: If it is allowed to check only once to see if the bulb is lit or not (this is not visible from the outside), how can you determine which of the three switches turns on the light bulb?

[Edited on 2-4-2005 by kiwirobin]

[Edited on 2-4-2005 by kiwirobin]

2. ### BleysPhoenix Takes FlightStaff Member

Hmmm....

:bnghd:

Electrical connection that fires from the switch being turned up, wait a minute...hmmm I thought I knew the answer but something is not quite, adding up there.

:bash:

Nice one!

The solution

3 switches - A, B, and C

Step 1: Turn ON both A and B.

Step 2: Wait a few minutes, then turn OFF only B.

Step 3: Go into room. If the light is on, switch A controls it. If the light is off, feel the bulb. If it is hot, then switch B controls it. If it is cold, switch C controls it.

:lb: :lb: :lb: :lb: :lb: