Change the lightbulb

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This is inspired by the post about multiple choice tests . I was a nuke in the Navy (Nuclear operator….reactor plants, not weapons). The training was extensive, and there wasn’t a multiple choice test in the entire program. You were graded on knowledge, not trivia. (You got more points for explaining the right answer, without knowing the actual terminology, then just writing down the right answer.)

Anyhow, here is a question I used to ask people that came to me to qualify for a few of the watches (jobs) in the plant. I’ll preface this by saying that the engine room in question supplies all utilities of the ship, from propulsion to fresh water.

Where is the only incandescent lightbulb in the entire plant, and why?

Enjoy!

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Just a random guess…

Did you use an ultraviolet light source to sterilise the water?

StuartR

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Nope, plain old incandescent light bulb.

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1] Is it give some indication of the electricity supply generation, varying intensity with the voltage available?
2] Or is it to keep the chief engineer’s pet hampster warm and happy?

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Number 1 is VERY close. It’s NOT an ‘indication’ light….there’s a little hint. It illuminates something….but WHY?

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Some sort of stroboscopic effect? (I remember variable speed turntables that used a neon pulsing at 100/120Hz to ‘freeze’ a pattern on the side of the revolving platter….)

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You’re pretty warm……just think about it for a bit……

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The exit sign?

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Funny, no. This is a plain old lightbulb. One you can buy in almost any store.

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Funny, no. This is a plain old lightbulb. One you can buy in almost any store.

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The exit sign?

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Drew

Could it be the emergency light that switches on when something goes wrong with the reactor?

Jerry

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No, in fact, it’s always on when there is power.

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No, in fact, it’s always on when there is power.

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Drew

Could it be the emergency light that switches on when something goes wrong with the reactor?

Jerry

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You’re pretty warm……just think about it for a bit……

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Some sort of stroboscopic effect? (I remember variable speed turntables that used a neon pulsing at 100/120Hz to ‘freeze’ a pattern on the side of the revolving platter….)

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My guess is that it illuminates the main switches to the generators.

Alan

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Hand-held torch as a source of emergency lighting?

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Hand-held torch as a source of emergency lighting?

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Between you and Leif, you almost have it.

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My thoughts were that it was a lamp, independent of any substantial power supply (main or auxilliiary) that required only a small, portable supply. An incandescent filament will do something at (just about) any voltage, while a fluoro requires a minimum (thus the difficulties of using fluoros with traditional dimmers). On this basis, a flashlight would qualify, but flashlights can go walkabout. So perhaps a fixed lamp connected to something like a low voltage rechargable battery.

But as to its purpose, perhaps it’s the lamp that switches on (via relay say) when the line voltage is down, or drops below a threshold value? Also provides light over the required controls/ instruments in such a case?

Alan

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My thoughts were that it was a lamp, independent of any substantial power supply (main or auxilliiary) that required only a small, portable supply. An incandescent filament will do something at (just about) any voltage, while a fluoro requires a minimum (thus the difficulties of using fluoros with traditional dimmers). On this basis, a flashlight would qualify, but flashlights can go walkabout. So perhaps a fixed lamp connected to something like a low voltage rechargable battery.

But as to its purpose, perhaps it’s the lamp that switches on (via relay say) when the line voltage is down, or drops below a threshold value? Also provides light over the required controls/ instruments in such a case?

Alan

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Between you and Leif, you almost have it.

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My guess is that it illuminates the main switches to the generators.

Alan

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Number 1 is VERY close. It’s NOT an ‘indication’ light….there’s a little hint. It illuminates something….but WHY?

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1] Is it give some indication of the electricity supply generation, varying intensity with the voltage available?
2] Or is it to keep the chief engineer’s pet hampster warm and happy?

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Nope, plain old incandescent light bulb.

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Just a random guess…

Did you use an ultraviolet light source to sterilise the water?

StuartR

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What about lighting an photoelectric cell that sounds a (battery powered) warning if it looses power from the photoelectric cell

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Isn’t that like the guy diving into the tub, as part of the trigger for catching a mouse in the ‘Mouse Trap’ game. LOL. Not even close Tim, sorry.

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Isn’t that like the guy diving into the tub, as part of the trigger for catching a mouse in the ‘Mouse Trap’ game. LOL. Not even close Tim, sorry.

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What about lighting an photoelectric cell that sounds a (battery powered) warning if it looses power from the photoelectric cell

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Or you just hire that guy that walks around and says – “is it working now”

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Or you just hire that guy that walks around and says – “is it working now”

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I think I have it.

If the plant shuts down all the lights etc will go out so you won’t see where you are going, so you will need a torch to find the fuse box, or whatever.

The incandescent bulb is in your torch.

Jerry

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I think I have it.

If the plant shuts down all the lights etc will go out so you won’t see where you are going, so you will need a torch to find the fuse box, or whatever.

The incandescent bulb is in your torch.

Jerry

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Actually, if the reactor goes down, there are emergency deisel generators that kick in. It’s impossible to start naval reactors without some source of power.

Okay folks, Leif and Alan were getting pretty close, then everyone started to go off the deep end with this one. So here is one last final hint.

What is the difference between a Flourescent light and an Incandescent light? What is the difference in how they work?

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Ok, since I was soooo off track – I thought that I would hunt this stuff down. Looking at http://www.howstuffworks.com/fluorescent-lamp.htm%5B/url%5D …

So, after working thru all that, the main difference is that a flourescent light emits photons in the ultraviolet wavelength range or am I still overboard?

Soooooo, if the flourescent light is connected to the reactor and NOT the battery power, and you have a sign that says “REACTOR IS ON” under the light that is only visible when viewed under flourescent light, you would know if the reactor was on or not without having to stick your head thru the reactor door?

No, that doesn’t make any sense – you could just look at the flourescent light to see if the reactor was on or not (light would be on or not).

hmmmmmmmmmmmm

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ROTFLMAO! Very intriguing. Not to confuse this subject, but ironically, a flourescent lightbulb actually works on the Geiger Mueller Principle . That link shows a geiger-mueller chart, I think on the second page. There is a platue on that chart, where ‘geiger counters’ work. voltages within that platue produce a equal ratio of radioactive interaction, and hits on the outside element of a geiger mueller tube. Voltages lower then that, create lower ratios (because some ‘reactions’ recombine before hitting the outside element), and voltages higher then that create a cascading effect, where it ‘floods’ the tube, because one reaction creates a never ending chain reaction. That higher voltage section is what flourescent lights are based on.

But back to the original puzzle, the reason an Incandescent light is used, has absolutely nothing to do with the reactor itself, nor radiation.

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Ok, so apart from being way off track and trying to work out why a sub only has one flourescent light … what I should have been thinking about is why a sub only has one incandescent light.

Ok, does an incandescent light glow brighter with higher volts? I think it does because everytime I iron my shirt, the lights dim when the iron clicks on. This would imply that the single incandescent light is a crude volt meter that the crew doesn’t have to watch – they can just tell by the brightness (or dimness) that the voltage is outside the ‘safe’ range.

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ROTFLMAO! Very intriguing. Not to confuse this subject, but ironically, a flourescent lightbulb actually works on the Geiger Mueller Principle . That link shows a geiger-mueller chart, I think on the second page. There is a platue on that chart, where ‘geiger counters’ work. voltages within that platue produce a equal ratio of radioactive interaction, and hits on the outside element of a geiger mueller tube. Voltages lower then that, create lower ratios (because some ‘reactions’ recombine before hitting the outside element), and voltages higher then that create a cascading effect, where it ‘floods’ the tube, because one reaction creates a never ending chain reaction. That higher voltage section is what flourescent lights are based on.

But back to the original puzzle, the reason an Incandescent light is used, has absolutely nothing to do with the reactor itself, nor radiation.

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Ok, since I was soooo off track – I thought that I would hunt this stuff down. Looking at http://www.howstuffworks.com/fluorescent-lamp.htm%5B/url%5D …

So, after working thru all that, the main difference is that a flourescent light emits photons in the ultraviolet wavelength range or am I still overboard?

Soooooo, if the flourescent light is connected to the reactor and NOT the battery power, and you have a sign that says “REACTOR IS ON” under the light that is only visible when viewed under flourescent light, you would know if the reactor was on or not without having to stick your head thru the reactor door?

No, that doesn’t make any sense – you could just look at the flourescent light to see if the reactor was on or not (light would be on or not).

hmmmmmmmmmmmm

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I can’t believe that it is used purely as a light source as there are many alternatives available that are more reliable and efficient. The question appears to ask why specifically an incandescent bulb.

Based on what you’ve said, I’m going to guess that it is to overcome the stroboscopic effect of fluorescent lamps when viewing monitors etc.

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So close. You got the why, but you changed the where.

Here it is:
The incandescent lights are over the generators, actually directly over the shafts between the turbine and the generator. The generators spin at 3600 RPM, to produce 480v (I think) AC at 60Hz. 60 Hz. is 60 times a second, or 3,600 times a minute. Since the generators supply the current for the ship, they are going to spin at the exact frequency of the AC power they produce. So, if you put only flourescent lights over the generator, you will get a stroboscopic effect, which would make the shaft appear to not be moving.

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hey – that shaft isn’t moving – something must be wrong, I better replace it

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Actually, it wasn’t uncommon to be climbing all over those things, cleaning, painting, etc. In a running engine room, it’s almost hard to tell if what you are climbing on is running, or if it’s just the room that is shaking! So it’s more for safety, to prevent anyone from thinking that ‘stationary’ shaft would be a good place to put their foot for a second….cause it would really be a good place to lose your foot in a second!

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yeah – that is what I thought – thus the guy at the end who explodes when he replaces it.

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yeah – that is what I thought – thus the guy at the end who explodes when he replaces it.

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Actually, it wasn’t uncommon to be climbing all over those things, cleaning, painting, etc. In a running engine room, it’s almost hard to tell if what you are climbing on is running, or if it’s just the room that is shaking! So it’s more for safety, to prevent anyone from thinking that ‘stationary’ shaft would be a good place to put their foot for a second….cause it would really be a good place to lose your foot in a second!

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hey – that shaft isn’t moving – something must be wrong, I better replace it

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So close. You got the why, but you changed the where.

Here it is:
The incandescent lights are over the generators, actually directly over the shafts between the turbine and the generator. The generators spin at 3600 RPM, to produce 480v (I think) AC at 60Hz. 60 Hz. is 60 times a second, or 3,600 times a minute. Since the generators supply the current for the ship, they are going to spin at the exact frequency of the AC power they produce. So, if you put only flourescent lights over the generator, you will get a stroboscopic effect, which would make the shaft appear to not be moving.

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I can’t believe that it is used purely as a light source as there are many alternatives available that are more reliable and efficient. The question appears to ask why specifically an incandescent bulb.

Based on what you’ve said, I’m going to guess that it is to overcome the stroboscopic effect of fluorescent lamps when viewing monitors etc.

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Actually, if the reactor goes down, there are emergency deisel generators that kick in. It’s impossible to start naval reactors without some source of power.

Okay folks, Leif and Alan were getting pretty close, then everyone started to go off the deep end with this one. So here is one last final hint.

What is the difference between a Flourescent light and an Incandescent light? What is the difference in how they work?

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Many blue moons ago, I was a submariner on hunter-killer nuclear subs working back aft as a health physicist. I have given your puzzle some considerable thought (to no avail) and I am preparing to give myself a heavy kicking once the solution is revealed.

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I don’t post many puzzles….so I don’t know how long I should wait before posting the answer……

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I work on the following principles:
If no, or very limited responses, then I provide clues after two days.
If a good deal of interest is generated (pun intended), then wait until an explicit request for a solution is made.
Or none of the above, depending upon my mood.

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I work on the following principles:
If no, or very limited responses, then I provide clues after two days.
If a good deal of interest is generated (pun intended), then wait until an explicit request for a solution is made.
Or none of the above, depending upon my mood.

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I’d think it has something to do with the magnetic field used by flourescent lights but not by incandescent, but I’m stuck about how that field would be changed by the reactor. The only magnetic field I can think of associated with reactors is the EMP associated with a nuclear explosion-and not even an incandescent light would survive one of those!

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I’d think it has something to do with the magnetic field used by flourescent lights but not by incandescent, but I’m stuck about how that field would be changed by the reactor. The only magnetic field I can think of associated with reactors is the EMP associated with a nuclear explosion-and not even an incandescent light would survive one of those!

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I don’t post many puzzles….so I don’t know how long I should wait before posting the answer……

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Many blue moons ago, I was a submariner on hunter-killer nuclear subs working back aft as a health physicist. I have given your puzzle some considerable thought (to no avail) and I am preparing to give myself a heavy kicking once the solution is revealed.

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Where is the only incandescent lightbulb in the entire plant, and why?
—————————————————————————————–
I am confused by the terminology. What do you mean exactly by the term plant ?

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Good question. By plant I mean engine room. A little more detail, hopefully this will help a little. On my ship (which was an aircraft carrier…not a sub, but this ‘puzzle’ would apply to all ships (more then likely non-nuke too)), we had 2 reactors. Each reactor was in a RAR (Reactor Auxillary Room), and each RAR had an associated MMR (Main Machinery Room). So there were four ‘rooms’ all together. The term ‘plant’ is really short for ‘power plant’, which is technically the combination of an RAR and an MMR. In reality, each RAR and MMR had 2 incandescent lightbulbs each. That may have confused the issue, but hopefully it will get everyone off of the radiation kick. This has nothing to do with radiation. (MMR’s didn’t have a reactor, just received Steam from the reactors in the RARs.)

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Good question. By plant I mean engine room. A little more detail, hopefully this will help a little. On my ship (which was an aircraft carrier…not a sub, but this ‘puzzle’ would apply to all ships (more then likely non-nuke too)), we had 2 reactors. Each reactor was in a RAR (Reactor Auxillary Room), and each RAR had an associated MMR (Main Machinery Room). So there were four ‘rooms’ all together. The term ‘plant’ is really short for ‘power plant’, which is technically the combination of an RAR and an MMR. In reality, each RAR and MMR had 2 incandescent lightbulbs each. That may have confused the issue, but hopefully it will get everyone off of the radiation kick. This has nothing to do with radiation. (MMR’s didn’t have a reactor, just received Steam from the reactors in the RARs.)

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Where is the only incandescent lightbulb in the entire plant, and why?
—————————————————————————————–
I am confused by the terminology. What do you mean exactly by the term plant ?

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Well, if nothing else, Drew, I think you can safely say that you wouldn’t be hiring any of our fellow loungers for the job!!

Including me, I might add – I haven’t the faintest idea!

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Well, if nothing else, Drew, I think you can safely say that you wouldn’t be hiring any of our fellow loungers for the job!!

Including me, I might add – I haven’t the faintest idea!

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