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 2 years ago
A light bulb is hanging in a room. Outside
of the room there are three switches, of
which only one is connected to the lamp.
In the starting situation, all switches are
'off' and the bulb is not lit. If it is allowed
to check in the room only once to see if the
bulb is lit or not (this is not visible from the
outside), how can you determine with which
of the three switches the light bulb can be
switched on?
 2 years ago
A light bulb is hanging in a room. Outside of the room there are three switches, of which only one is connected to the lamp. In the starting situation, all switches are 'off' and the bulb is not lit. If it is allowed to check in the room only once to see if the bulb is lit or not (this is not visible from the outside), how can you determine with which of the three switches the light bulb can be switched on?

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apoorvk
 2 years ago
Best ResponseYou've already chosen the best response.4NAHI!! i typed out a long solution for this one but lost it due to server restart. that alien feeling _/(o.O)\_ okay so a similar question was also posted by Prof Walter Lewin recently(albeit easier) (though I managed to cracked it there as well :p) SO, name the three switches as A, B and C. Now switch on A, say for about 15 mins. Then switch it off. Now, switch on B. and immediately enter the room. Now the following are results corresponding to what you find inside: A if the bulb is unlit, but the glass cover outside is hot due to radiations from the filament. B if the bulb is is lit. C if the bulb is BOTH unlit, as well as feels cold, or room temperaturelike. Am I right? :)

Aadarsh
 2 years ago
Best ResponseYou've already chosen the best response.2@sheena101 didi, can u try this?

Aadarsh
 2 years ago
Best ResponseYou've already chosen the best response.2Please sister. Try something.

Aadarsh
 2 years ago
Best ResponseYou've already chosen the best response.2@sheena101 Please give me a medal also.

heena
 2 years ago
Best ResponseYou've already chosen the best response.0better ask ur freind to stand in the room and den ask him when light i lit he will shout and tell u simple :P

ujjwal
 2 years ago
Best ResponseYou've already chosen the best response.0is there a key hole in the door??

apoorvk
 2 years ago
Best ResponseYou've already chosen the best response.4unfortunately, your friend is very busy according to question, and currently unavailable.

Aadarsh
 2 years ago
Best ResponseYou've already chosen the best response.2@heena didi, ur response is a bit witty. But, the thing is that only one person is allowed to do this. I think, @apoorvk bhaiya's answer is correct. Anyway, thanks my sister.

Aadarsh
 2 years ago
Best ResponseYou've already chosen the best response.2@sheena101 didi, thanks for the medal. Yippee!!!!!

Aadarsh
 2 years ago
Best ResponseYou've already chosen the best response.2@ujjwal bhai, there is no key hole in the door as given.

heena
 2 years ago
Best ResponseYou've already chosen the best response.0ok guys i forgot to write dat i was joking dat time actually i had a cutt off anyways apporv an is right i think evn i also dunno :P

Aadarsh
 2 years ago
Best ResponseYou've already chosen the best response.2hehhehehe heena didi. Nice joke.
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