In a room, there are three light switches outside that control three light bulbs inside. You can only enter the room once. How do you determine which switch controls which bulb?
Category: Brain Teasers · Difficulty: medium
Hint: Consider how you can use warmth to help identify the bulbs.
Answer
Turn on the first switch, wait a moment, then turn it off and switch on the second one.
Explanation
By turning on the first switch and letting the bulb warm up, then turning it off and turning on the second switch, you can identify the bulbs by their heat and light.
This is a medium brain teasers riddle — a moderate challenge for most people. The answer is Turn on the first switch, wait a moment, then turn it off and switch on the second one..
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