3 bulbs and 3 switches | Logical Puzzles Solution | Puzzle asked in Interview

There are 3 bulbs(B1, B2 and B3) in a room on 1st floor, they can be operated using 3 switches(S1, S2, S3) present on the ground floor. You don’t know which Switch is for which bulb. How can you figure out, which switch is for which bulb if you are allowed to visit 1st floor only once.

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Assuming all switches are turned off initially, You can do the following:-

1.) Turn on switch S1 for 5 minutes.

2.) Turn Off switch S1.

3.) Turn on switch S2.

4.) Go Upstairs.

5.) Glowing bulb can be assigned to Switch S2.

6.) Touch both other bulbs, hotter one should be assigned to switch S1 and the other one to switch S3.