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How can you figure out which light switch goes to which light bulb by only making 1 trip upstairs?

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There are 3 switches downstairs, each corresponding to one of the light bulbs upstairs.
How can you figure out which light switch goes to which light bulb by only making 1 trip upstairs?

posted Jan 12 by Prithvi

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2 Answers

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You turn on one light bulb. Leave it on for a while. Then, turn that one off and turn another one on. Go upstairs. One light bulb will be cold, one will be warm, and one will be on.

answer Jan 12 by Yasin Hossain Siinan
0 votes

When a bulb is left on for some minutes, it will get heated up.
So turn 1st switch on and leave for considerable amount of time so that corresponding bulb will be heated up.
Now turn 1st one off and turn on 2nd one,
Then upstairs.

The bulb which is glowing is of second switch.
The bulb which is hot and not glowing now, is of first switch.
The bulb which is cool and also not glowing is of third switch.

answer Jan 15 by Varun Bankapur



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