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  • Feb 4, 2014, 01:20 PM
    hello94857
    Electrcity and gravity
    Is there any field of energy or material that can contain neutrons ?
  • Feb 4, 2014, 01:22 PM
    smoothy
    Sounds like a homework question.
  • Feb 4, 2014, 02:02 PM
    ebaines
    Smoothy - this does not sound like a homework question to me - it's a bit off the wall.

    To the OP: free neutrons can't be contained like water in a glass. Since they are neutral charge you can't build a "magnetic bottle" or other device to constrain them separate from the container they're in. Generally what happens is the free neutrons pass into the material of the container and ultimately are absorbed within the nuclei of atoms that make up the container, and thus create alternative isotopes of that material (which may make the material radioactive).
  • Feb 4, 2014, 06:55 PM
    ma0641
    Not sure what you may be considering but, graphite is used in nuclear reactors as neutron absorbers.
  • Feb 5, 2014, 05:53 PM
    hello94857
    Electricity
    Obviously a piece of copper wire can only hold so much electricity, what is the ratio for the amount of electricity to the width and distance of wire ? Would the ratio of electric to wire change for different types of wire ?

    How can the above information be used to make a transformer ?

    In a transformer the copper wire is turned round steel plates, why are the steel plates there ?
  • Feb 5, 2014, 08:12 PM
    smearcase
    You are doing very well so far.
    You are on the right track.
  • Feb 5, 2014, 09:18 PM
    ma0641
    Google "inductance" to learn about how a transformer works..
  • Feb 6, 2014, 06:45 AM
    ebaines
    A wire doesn't "hold" electricity the way a pipe holds water, if that's what yuo're thinking. Wires carry current, whichis the flow of electrons. A coper wire is a very good conductor compared to, say, a piece of wood, so electrons can flow through a copper wire much more easily than throufgh a piece of wood. The ability of a wire to carry electric current is called conductance, and in general the higher the conductance the less loss of power ter is due to resistive heating. The conductance of a piece of wire is proportional to its cross-sectional area (at least for low frequency applications), so if you double the diamater of the copper wire it can carry 4 times as much current with the same amount of loss. Other metals such as steel or aluminum can be used for wire, with some difference in conductance for each material.

    As for transformers: the steel (actually iron) plates in a transformer are known as the core - they serve to carry magnetic fields between the windings of the transformer. The way a transformer works is the alternating current in one coil creates a magnetic field insde the coil, the strength of which depends on the number of turns of wire in the coil; the iron loop inside that winding picks up the magnetic filed transfers it to inside the second coil, and there the varying magnetic field induces a voltage into the second winding, the volatege of which is dfependent on the number fo turns of wire of the 2nd coil. The ratio of voltages between the first and second coil works out to be equal to the ratio of the number of windings between the first and second coil. In this way AC voltages can be stepped up or down through the transformer.
  • Feb 6, 2014, 07:48 AM
    hello94857
    Behaviour of electricity
    If there where a single strand of 0.9 copper wire at a length of 1cm how much current could potentially occupy the surface ? Would this double if the length of the wire doubles ?

    How do the soft iron (mild steel) plates effect a transformer ?
  • Feb 6, 2014, 08:42 AM
    ebaines
    Current carrying capability of a wire is not affected by length. The current capacity of a 0.9mm diameter copper wire (about 19 AWG) is about 10A. This assumes low frequency current. You mentioned capacity of the surface of the wire - why? Are you considering high frequency AC current? (several megahertz or higher)? Electrons generally flow through the core of the wire, but may be limited to the surface if the frequency is high.

    I addressed the function of the core in your other post. See: https://www.askmehelpdesk.com/physic...ty-783606.html if you have additional follow up questions it's better to post the question in the original thread as opposed to starting a new thread.
  • Feb 6, 2014, 06:44 PM
    hello94857
    A coil used in generating
    If there where a coil next to a rotating magnet (1500)rpm ,

    The core of the coil is 15mm long 16mm depth and 5mm width with 2 meters of 0.9 enameled copper wire wound around it, how much electricity would it produce per pass of the magnet? and how (please with calculus with explanation of calculus) would one work it out ?
  • Feb 6, 2014, 06:58 PM
    hello94857
    Yes I was considering a high frequency of an A.C current in generators.
  • Feb 6, 2014, 06:59 PM
    hello94857
    Wire efficiency for electricity?
    How would hollow wire help the efficiency of the wire?
  • Feb 6, 2014, 07:15 PM
    Cat1864
    I have merged your questions on Electricity into one thread. Please keep all questions on this subject in this thread.

    Is this curiosity or school/home work? These questions are sounding more and more like they are coming from a textbook.
  • Feb 7, 2014, 07:56 AM
    physic
    Neutron star - Wikipedia, the free encyclopedia
  • Feb 7, 2014, 08:10 AM
    ebaines
    Quote:

    Originally Posted by hello94857 View Post
    How would hollow wire help the efficiency of the wire?

    Could provide some cost savings on material, but the added cost and complexity of manufacturing makes it impractical except for perhaps some very special applications. Rather than a hollow design a construction that may make sense is to use steel or aluminum as a core with copper cladding. What frequency signal are you interested in?
  • Feb 7, 2014, 09:30 AM
    ebaines
    Quote:

    Originally Posted by hello94857 View Post
    If there where a coil next to a rotating magnet (1500)rpm ,

    The core of the coil is 15mm long 16mm depth and 5mm width with 2 meters of 0.9 enameled copper wire wound around it, how much electricity would it produce per pass of the magnet? and how (please with calculus with explanation of calculus) would one work it out ?

    The EMF induced in the coil from Faraday's Law:




    where N is the number of coils and is the magnetic flux, in webers. So it depends on the strength of the magnet and speed of magnet movement relative to the coil.
  • Feb 7, 2014, 10:23 AM
    ebaines
    Quote:

    Originally Posted by hello94857 View Post
    Yes I was considering a high frequency of an A.C current in generators.

    Quote:

    Originally Posted by hello94857
    If there where a coil next to a rotating magnet (1500)rpm

    1500 Hz is not considered to be high frequency. Your questions about conductance on the surface of the wire and hollow wires do not apply unless you are talking the MHz range and higher.
  • Feb 10, 2014, 07:56 PM
    smoothy
    Announcements - Homework Help

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