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Speed Of Light

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  • 30-11-2011 5:22pm
    #1
    FrankKay
    Registered Users Posts: 28 ✭


    How Does The Speed Of Light Work ?


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    #2
    Morbert
    Registered Users Posts: 3,457 ✭✭✭Morbert


    FrankKay wrote: »
    How Does The Speed Of Light Work ?

    It is derived from the 4 equations of electromagnetism:

    Gauss's law

    Gauss's (magnetism) law

    Farady's law

    Ampere's circuital law

    How much math do you know? I can post a raw derivation if that would be helpful. In a nutshell, the above equations show that the electric and magnetic field (it's really all the same "electromagnetic" field) interact in such a way that electromagnetic waves propagate at speed c.


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    #3
    krd
    Banned (with Prison Access) Posts: 3,455 ✭✭✭krd


    Morbert wrote: »

    How much math do you know? I can post a raw derivation if that would be helpful.


    Could you?........I would be very grateful if you did - I've never seen the derivation.


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    #4
    ray giraffe
    Registered Users Posts: 338 ✭✭ray giraffe


    FrankKay wrote: »
    How Does The Speed Of Light Work ?

    About a million times faster than sound, which is roughly a million times faster than a snail. :cool:


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    #5
    sponsoredwalk
    Registered Users Posts: 3,038 ✭✭✭sponsoredwalk


    I'd say you'd appreciate this.


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    #6
    krd
    Banned (with Prison Access) Posts: 3,455 ✭✭✭krd


    sponsoredwalk wrote: »
    I'd say you'd appreciate this.

    Thank you.


    I would really like to see Morbert lay out the derivation - in say an image form (not in horrible ASCII maths) - so I could scan through and have my "aw haw" moment.

    Morbert, I would be eternally grateful if you could show us a little art an narrative - and dazzle the ignorant. Myself being an ignorant islander.


    Please...show us the magic. :)


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    #7
    FISMA
    Closed Accounts Posts: 2,616 ✭✭✭FISMA


    krd wrote: »
    Thank you.


    I would really like to see Morbert lay out the derivation - in say an image form (not in horrible ASCII maths) - so I could scan through and have my "aw haw" moment.

    Morbert, I would be eternally grateful if you could show us a little art an narrative - and dazzle the ignorant. Myself being an ignorant islander.


    Please...show us the magic. :)

    They're not too bad in integral form, if you get calculus. Otherwise, they're still digestible if you just think of summing lots and lots of things things up. They can be intimidating when you see the atled (upside down delta) - in differential form.

    True elegance - Maxwell's equations. Even Einstein gave "props" to Maxwell since his laws, unlike Newtons, needed no tweaking when close to the speed of light.

    Here's a good place to start.

    If you "get" Coulomb's Law, than Gauss should not be a problem. We use Gauss' Law when we are able to make use of symmetry, such as surrounding an object by a sphere or cylinder. If you cannot exploit symmetry then Gauss' Law isn't going to be of much use to you as the integration just gets messy.

    I have a few ppt's that I could post which may help.


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    #8
    Morbert
    Registered Users Posts: 3,457 ✭✭✭Morbert


    I wrote a post but the math didn't work so instead I've transferred it to this pdf.


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    #9
    FISMA
    Closed Accounts Posts: 2,616 ✭✭✭FISMA


    Morbert wrote: »
    I wrote a post but the math didn't work so instead I've transferred it to this pdf.

    Morbert, have you a similar proof in integral form?

    The div-grad-curl and all that stuff isn't my favorite look and feel. :o


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    #10
    krd
    Banned (with Prison Access) Posts: 3,455 ✭✭✭krd


    Morbert wrote: »
    I wrote a post but the math didn't work so instead I've transferred it to this pdf.

    Thanks. I really don't understand all that maths. Gives me somewhere to start. It's years since I've studied - there are so many things I've forgotten how to do - or don't even remember how I studied them (or what I may have consciously picked to avoid -due to lack of time and comprehension and other things)

    I can see something in the equations though I'd need to go over bits of it individually to clearly see what's going on.


    I was just watching Caltech: The Mechanical Universe - 11 - Gravity, Electricity, Magnetism

    They do an interesting derivation using experimentally derived values.

    The magnetic and electric constant. Derived experimentally via the force equations.

    Ke = 9X10^9 Nm^2/C^2

    Km = 1x10^-7 Ns^2/C^2

    Divide them

    Ke/Km = 9 x 10^16 m^2/s^2 Which looks like the square of the speed of something


    sqrt(Ke/Km) = 3x10^8 ms^-1 Which is the experimentally derived speed for light, c. Which would indicate a fundamental relationship between light, electricity, and magnetism.

    I can see the relationship. There's quite a bit of maths I'd need to revise (and learn) before I would see it jumping off the page at me.


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    #11
    goldenwonder
    Registered Users Posts: 191 ✭✭goldenwonder


    299,792,458 metres per second in a vacuum, and acts as mass and energy according to the slit experiment.
    but simple trigonometry can go beyond that speed theoretically
    the absolute hassle of light


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