Question

You are standing in front of a room with one light bulb inside of it. You cannot see if it is on or off. Outside the room there are 3 switches in the off positions. You may turn the switches any way you want to. You stop turning the switches, enter the room and know which switch controls the light bulb. How?

Answer 1

To know which switch controls the light bulb,

1. Turn two switches on among three.

2. Wait 3-4 minutes.

3. Now turn on one switch and enter the room.

4. Touch the light bulb, if it is then the on switch is its trigger.

If not lit but warm then the switch you turned off is the trigger. If the bulb is cold then the off switch is the trigger.