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sunlight

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vincenthooi

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i always wondered.... how much output is sunlight on a sunny afternoon(in mw terms)
and how does 3x magnified sunlight fare with lasers.., i know it is not collaminated.. but it sure is strong at max focus.
anybody ever tried measuring the output?
 





M

Murudai

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That's actually an interesting idea. Interesting indeed.

So if someone has a thermal meter, go outside with a magnifying glass and tell us the results :)
 
N

nikokapo

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gotta go to sleep, but why not ask it in the science section? (i read that more often)
 
V

vincenthooi

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nikokapo said:
gotta go to sleep, but why not ask it in the science section? (i read that more often)
Click to expand...
because i dint thought about it... ::)

i am quite sure it is much lower than kw range.. i mean... those 3w lasers can burn white paper much better than sunlight under a magnifying glass, and 1-4kw probably will cut metal
 
GooeyGus

GooeyGus

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pseudolobster said:
I heard it was 1000W/m[sup]2[/sup]
Click to expand...

bingo  ;) The "solar constant" is a measure of the constant power coming from the sun. I think it's about 1300W/m[sup]2[/sup] at 93 million miles (one astronomical unit, also known as the distance between sun and earth) But after the light comes through our atmosphere its around 1000W/m[sup]2[/sup]

Also, as far as total power of the sun, the answers vary a bit. I would say the median answer would be 4 × 10^26 watts.

"Four-hundred septillion watts. That's 400 trillion-trillion watts!" (Mr. Bill Nye the science guy)
 
N

nikokapo

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there's a youtube video where some guys use a fresnel to burn some wood..

but yeah, it depends on the area ;)
 
RA_pierce

RA_pierce

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vincenthooi said:
i am quite sure it is much lower than kw range.. i mean... those 3w lasers can burn white paper much better than sunlight under a magnifying glass, and 1-4kw probably will cut metal
Click to expand...

Yeah and if you had a 1 meter fresnel lens you could probably cut metal.

The power depends on how big your lens/mirror is.
The larger area will focus more sunlight
You tube probably has some videos of guys melting pennies with a fresnel lens.

Here in Southern California on a sunny day I can set wood on fire with a parabolic mirror (5 inch diameter) within a few seconds.

I think office depot has some page size magnifiers... I want one.
Overhead projectors also have nice big lenses... hmmm...
 
MarioMaster

MarioMaster

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i have a cheap 8.5" x 11" fresnel lens - it ignites wood and paper almost instantly
 
Switch

Switch

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vincenthooi said:
what about a the white spot under a 3x magnifying glass?
Click to expand...
That depends on the surface of your magnifying glass.A bigger one will focus more sunlight while a smaller one , less sunlight.BUT , the smaller one will focus it on a smaller spot than the larger one(providing they are both 3x) Energy density should be the same, so it will burn just the same, theoretically.It's just that the bigger lens will make a wider hole in a floppy disk at the same rate. :p

You can calculate the total power by dividing 1m[sup]2[/sup] to your magnifying glass' surface then divide 1kW by that.

Of course a 1m[sup]2[/sup] fresnel lens won't cut steel because it will have a focused spot of at least an inch or 2 so energy density will be too low.Maybe if you use additional lenses to make the dot a few mm wide.But I think the dot would be too bright for a welding mask then :D
 
Spyderz20x6

Spyderz20x6

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Can focused sun give you cancer if you shine it on your arm? It has all those UV and IR rays... *shudders*
 
Switch

Switch

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Spyderz20x6 said:
Can focused sun give you cancer if you shine it on your arm? It has all those UV and IR rays... *shudders*
Click to expand...
Yeah probably, especially with the recent depleating of the O[sub]3[/sub] layer. ::) They say you can get cancer just by over exposing yourself to sunlight.A magnifying glass should mean instacancer. ::) IR is harmless though, "harmlesser" than visible light, cancer wise.It's UV you should look out for.So if you wanna burn something in your arm use a UV filter on your lens.Or use a laser. :D (>500nm to be safe)
 
Spyderz20x6

Spyderz20x6

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Switch said:
[quote author=Spyderz20x6 link=1213155270/12#14 date=1213225406]Can focused sun give you cancer if you shine it on your arm? It has all those UV and IR rays... *shudders*
Click to expand...
Yeah probably, especially with the recent depleating of the O[sub]3[/sub] layer. ::) They say you can get cancer just by over exposing yourself to sunlight.A magnifying glass should mean instacancer. ::) IR is harmless though, "harmlesser" than visible light, cancer wise.It's UV you should look out for.So if you wanna burn something in your arm use a UV filter on your lens.Or use a laser. :D (>500nm to be safe)[/quote]
Can ants get cancer? ::)
What about the area around it (the light radiates)? Can focused sunlight be called a laser? i think sun-rays are coherent ;D
I have a 12x12 inch fresnel lens, and it burns...
 
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