Riddles, brain puzzles and mathematical problems

[BAndrew]

OK I think I figured it out!

Turn 2 switches on. Wait enough time just in case the light is on so the light bulb can increase temperature. Just when you are about to go to the room turn one switch off.

Case 1: If the light is open then the correct switch is the one you left open
Case 2: If there is no light, but the light bulb is "warm" then the correct switch is the one you turned off just before you went to the room
Case 3: If there is no light, but the light bulb is "cold" or "not hot" then the correct switch is the one you didn't touch.

That of course applies if that trick with the temperature can be done.