257 replies to this topic

[Incognitum]

but I want to thank you for this, because I used this trick to troubleshoot my brake lights (it's hard to view the bulb while sitting in the car pressing the brake pedal). I could have wedged something between the brake pedal and the seat, but I figured this would be easy enough, and it worked.

Dude, back your car into your driveway at night and look for the brake light glare against your garage door in the rear view mirror.

I don't object to the use of the term "logic," but most rooms I've been in you can't just reach up and touch a light bulb. Your premises were incomplete as they did not mention the light bulbs were in arm's reach (or are you using a ladder in the other room? Or a hot air balloon? You don't even tell us how you reach them).

An equaly good solution is to walk into the room and use your magic lightswich identifier box. ...Oops, sorry, did I forget to mention you had one of those?

It's kinda like that.

[the1trueriley]

Turn two of the three switches on. wait some time, turn one of them off. The switch that stays on will match the light that is on - the switch that was left off will match the cooler of the two off bulbs and the last switch that was turned on for some time and then turned off will be warmer than the other bulb that is off.

[bigbrainbrad]

ok, are these switches in my kitchen? because I have at least one switch that I really think the previous owners put there as a cruel joke. maybe they wired to a light at their new place that illuminates the word "SUCKER" every time I flip it.

[random person]

THESE ARE THE ANSWERS.

Turn on the first switch and then wait a few minutes.
Then turn it off and turn on the second switch right away and wait a few minutes.
Now turn off the second switch and walk into the other room.
Touch all of the bulbs and feel for which bulb is the hottest. This one is with the second switch.
The cooler, but still warm bulb is with the first switch.
The coolest bulb is the third switch.

The bulb with the first switch isnt the hottest becuz it had time to cool down while the 2nd switch's bulb was still hot.

YOU FOOLS SHOULDN'T HAVE WASTED 2 WEEKS ON THIS; IT DOESN'T TAKE THAT LONG TO FIGURE OUT THIS SIMPLE PROBLEM!

[Incognitum]

YOU FOOLS SHOULDN'T HAVE WASTED 2 WEEKS ON THIS; IT DOESN'T TAKE THAT LONG TO FIGURE OUT THIS SIMPLE PROBLEM!

Are you on stilts? How do you propose to touch the light bulbs? You make it sound simple in 1, 2, 3 instructions, but like I said, you could just as easily say:

1. Turn on one bulb, wait several minutes.

2. Turn off the first switch, and turn another one on.

3. Quickly walk into the room and pull out your magic switch detector to achieve the answer.

Neither reachable bulbs, nor a magic detector box is mentioned in the premises, so both are equally valid (IE invalid) when introduced at the conclusion.

[marcoiam]

Add a resistor in line on one of the switches. Turn the one w/ the resistor and any other single switch. Same principle as the turn on/off method, but it's what I came up with before reading the solution.

The dim light = Resistorized switch
On light = the On switch
Off light = the Off switch

[beanman]

I just "imagined" that the switches were in the same room as the bulbs

[ctryan]

Leave the 1st switch off, Turn 2nd switch on and then off after a few mins, 3rd switch stays on. Bulb to 1st switch is off, Bulb to 2nd switch is off but is warm, Bulb to 3rd switch is the one that remains on.

[rajiv621]

Assuming the bulbs are those where we can control the intensity we can easily identify which switch is for buld. Just rotate the switch to dim, middle and high point and go to the room. The buld which is brightest belongs to high point switch.

[chebden]

What if not all the lights are off when you start?