Recent content by Lambduh

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    Selective transmission/absorption of light based on amplitude?

    As Naty1 linked above saturable absorption works in a similar fashion to what you proposed. When light intensity is high enough, there aren't enough electrons left in the ground state(due to finite upper state lifetimes) to absorb incoming photons. Subsequently, transmission increases until...
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    Violet light produced from green He-Ne laser?

    If you have a spectrometer you could see what wavelength it is you're looking at and try to associate an emission line with it. I remember seeing a similar spectra/color when building a He-Ne laser sans enclosure on an optical bench. Remember that the light coming from the He-Ne is green...
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    Magnetic shielding

    Why would silver be better than iron or http://en.wikipedia.org/wiki/Mu-metal" [Broken]? Not only is silver very expensive, but it's magnetic permeability is low comparatively. If the frequencies you are trying to block are high enough then you can move to a Faraday Cage, but for low frequency...
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    Charger could be there connected to mains all the time

    If it was as simple as putting the voltage from the wall across the battery of your phone your reasoning would be correct. However, a phone charger has components in between the wall and the phone to condition the signal so it's usable to charge the phone. None of these components are perfectly...
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    How do I asses the % of light transmission that passes through glass

    The easiest/fastest way to completely characterize the glass in the way that ZaperZ is talking about is to use a spectrometer. There are a lot of cheap (relative of course, ~3kish) compact prism spectrometers that do an amazing job of this. The one i use all the time is an Ocean Optics HR-4000...
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    Mirages on road

    Woops, was in the process of editing my post above to make it more clear. Post again if you still have questions.
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    Mirages on road

    Probably because you're seeing a reflection of the blue sky. As you said the reason that you actually see the sky/horizon/whatever is that the air near the hot black road heats up and acts as a mirror. As air heats up the index of refraction changes. A gradient temperature near the road produces...
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    Laser Induced Breakdown Spectroscopy

    Maybe it's oxygen in the atmosphere is reabsorbing those photons? It would depend on the flux coming from your sample and the distance to and sensitivity of your spectrometer set up. There might be a more obvious reason, I'm no spectroscopist.
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    Urgent - fiber optics illumination system

    As far as delivering/accepting the light: The amount of light a fiber can collect is based on it's Numerical Aperture (NA). The math for this is based on a index of refraction of the core and a cladding that the fiber is made of. Basically the NA tells you which light will enter and stay in...
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    Traveling 60mph, is it really 88 feet/second?

    I figured it was about right but instead of multiplying it out i got lazy and used alpha like i do more and more these days. I have a hard time grasping what feels right at pretty much any speed :P But then again i run pretty slow...
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    Light seems to bend around objects but why?

    I believe this is diffraction not refraction. Refraction is the bending of light when it enters a medium with a different index of refraction, ie light entering water. This is why fish look like they are in one spot but are actually in another. Diffraction is the bending of light as is...
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    Intensity of LEDs

    For a simple resistor only circuit V=IR absolutely does hold true. Sure, things will heat up and the resistance will change but ohm's law still applies it's just that a new value for R must be used. Also, generally as metals heat up they become more resistive but as semiconductors heat up they...
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    Hydrogen Is Positive

    Is it possible that your teacher was talking about a molecule of water? H2O is a polar molecule and the positive side will be towards the hydrogen atoms. http://en.wikipedia.org/wiki/Polar_molecule
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    Journal Access, etc.

    Having recently lost access to my old universities online library and thus access to all of the journals that the college is subscribed to i am now seeking other means of accessing recent papers. Doing a bit of searching didn't turn up much unfortunately and as such i started thinking of what...
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    Worst Conductor Metal

    What f95toli said. For good hard insulators ceramics are great. Pretty much all we use in high vacuum environments. Teflon coated wires work great too but can't be heated like ceramics can. Also fired alumina is extremely hard and i've never actually broken or sheared a piece. I first...
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