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scott wrote:
>> for a wide band with low energy at any specific single wavelength to
>
> How can you have a "wide band" at a specific single wavelength? Surely
> the definition of a "band" is a range of wavelengths?
>
> Sure, if the peak is at 600 nm, then the energy in the band from 599.99
> to 600.01 will most likely be less than the band from 100 to 599.
What I actually meant was that a "peak" is just one wavelength with a
lot of energy. The band containing the peak isn't necessarily the band
with the highest total energy.
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Invisible <voi### [at] dev null> wrote:
> Sure. So if you know how hot the star is, you know roughly the shape of
> the entire emission spectrum. :-)
Yes. Except of course it works the other way around in practice.
> > think maybe lightbulbs peak in the IR (lower temperature), so all we see is a
> > section of the tail of the spectrum.
>
> The peak is just the single wavelength at which there is the most
> energy. I think if you look at *bands* of the spectrum, it's possible
> for a wide band with low energy at any specific single wavelength to
> have a greater total power and a band containing only a single
> high-power (but narrow) peak.
What Scott said. But I know what you mean - and yes, of course. I was just
explaining why most of an incandescent bulb's energy output is not in the
visible. Look at the shape of a blackbody spectrum for 3000K. Clearly, most of
the power output is IR and beyond.
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> Probably not nearly as important as the error introduced by assuming both
> star
> and bulb emit only in the visible.
Wikipedia can tell you the "luminous efficacy" of the sun (14%), a light
bulb (2%) and LEDs (1.5-22%):
http://en.wikipedia.org/wiki/Luminous_efficacy
Whilst the % values are not exactly the amount of radiation that is visible
(it's weighted more towards green), it's a better approximation than 100%
:-)
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> Wikipedia can tell you the "luminous efficacy" of the sun (14%), a light
> bulb (2%) and LEDs (1.5-22%):
Anybody happen to know the luminous efficacy of a glow worm?
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>> Wikipedia can tell you the "luminous efficacy" of the sun (14%), a light
>> bulb (2%) and LEDs (1.5-22%):
>
> Anybody happen to know the luminous efficacy of a glow worm?
Man Wikipedia knows everything! We should power our lights with glow worms!
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"scott" <sco### [at] scottcom> wrote:
> >> Wikipedia can tell you the "luminous efficacy" of the sun (14%), a light
> >> bulb (2%) and LEDs (1.5-22%):
> >
> > Anybody happen to know the luminous efficacy of a glow worm?
>
> Man Wikipedia knows everything! We should power our lights with glow worms!
All they need is a reflective cavity and a biochemical population inversion, and
we could have them in CD players too!
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>>> Anybody happen to know the luminous efficacy of a glow worm?
>> Man Wikipedia knows everything! We should power our lights with glow worms!
>
> All they need is a reflective cavity and a biochemical population inversion, and
> we could have them in CD players too!
...so I'm guessing it's quiet efficient then? (Mother Nature has an
uncanny way of doing this, it seems.)
Given the number of genetically engineered organisms which glow, I'm
guessing scientists have a good idea of how this works. Maybe
electronically-controlled glowing algae or something isn't so
far-fetched. (I hate to think what the component lifetime would be though!)
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Darren New <dne### [at] sanrrcom> wrote:
> No. The "interference" is caused not by the particle, but by the slits.
How does the photon know there was another slit nearby, and behave
differently if that was so?
--
- Warp
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Patrick Elliott <sel### [at] npgcablecom> wrote:
> Warp wrote:
> > when the state of the particle is "observed" (whatever that might mean)
> Merely that you have done something to it which changes its unknown
> state, usually causing it to make contact with another particle(s), such
> as a detector.
I think the Copenhagen interpretation goes beyond that. If the decay of
the radioactive substance causes the flask to be broken, killing the cat,
it has already been "observed" (by whatever detector caused the flask to
be broken) and thus there are no superimposed states, but according to
the Copenhagen interpretation there are, until some external observer opens
the box.
That's the kind of "observation" I don't understand.
--
- Warp
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Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> > It looks like a wave, it behaves like a wave, it produces all the effects
> > that a wave would produce, but it's not a wave.
> By the way, just so you know, this sort of statement comes across to me as
> sarcastic, as if you're ridiculing my statements. I don't know if that's
> your intention here, but that's why after a number of exchanges I sometimes
> get ruder than I need to be. I don't know if it's a communication issue or
> you getting frustrated at my inability to explain quantum mechanics in a
> 2-paragraph post ;-) but sometimes when you don't agree, your expressions of
> that lack of agreement (not necessarily disagreement, mind) sound sarcastic.
It was not sarcasm, it was puzzlement.
--
- Warp
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