How does the length of a wire affect its resistance? The longer the wire, the larger the resistance because...
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Causes of resistance\n[edit]\n\nIn metals\n\nA metal consists of a lattice of atoms, each with a shell of electrons. This can also be known as positive ionic lattice. The outer electrons are free to dissociate from their parent atoms and travel through the lattice, creating a 'sea' of electrons, making the metal a conductor. When an electrical potential difference (a voltage) is applied across the metal, the electrons drift from one end of the conductor to the other under the influence of the electric field.\n\nIn a metal the thermal motion of ions is the primary source of scattering of electrons (due to destructive interference of free electron wave on non-correlating potentials of ions) - thus the prime cause of metal resistance. Imperfections of lattice also contribute into resistance, although their contribution in pure metals is negligible.\n\nThe larger the cross-sectional area of the conductor, the more electrons are available to carry the current, so the lower the resistance. The longer the conductor, the more scattering events occur in each electron's path through the material, so the higher the resistance. [1]\n[edit]\n\nIn semiconductors and insulators\n\nSemiconductors have properties that are part-way between those of metals and of insulators. A silicon boule has a grayish metallic sheen, like a metal, but is brittle, like glass. It is possible to manipulate the resistive properties of semiconductor materials by doping those materials with atomic elements, such as arsenic or boron, which create electrons or holes which can move across the material lattice.\n[edit]\n\nIn ionic liquids/electrolytes\n\nIn electrolytes, electrical conduction happens not by band electrons or holes, but by full atomic species (ions) traveling, each carrying an electrical charge. The resistivity of ionic liquids varies tremendously by the salt concentration - while distilled water is almost an insulator, salt water is a very efficient electrical conductor. In biological membranes, currents are carried by ionic salts. Small holes in the membranes, called ion channels, are selective to specific ions and determine the membrane resistance.\n[edit]\n\nResistance of various materials\nMaterial Resistivity, ρ\nohm-meter\nMetals 10 - 8\nSemiconductors variable\nElectrolytes variable\nInsulators 1016\n[edit]\n\nBand theory\nElectron energy levels in an insulator.\nElectron energy levels in an insulator.\n\nQuantum mechanics states that the energy of an electron in an atom cannot be any arbitrary value. Rather, there are fixed energy levels which the electrons can occupy, and values in between these levels are impossible. The energy levels are grouped into two bands: the valence band and the conduction band (the latter is generally above the former). Electrons in the conduction band may move freely throughout the substance in the presence of an electrical field.\n\nIn insulators and semiconductors, the atoms in the substance influence each other such that between the valence band and the conduction band, there exists a forbidden band of energy levels that the electrons simply cannot occupy. In order for a current to flow, a relatively large amount of energy must be furnished to an electron for it to leap across this forbidden gap and into the conduction band. Thus, large voltages yield relatively small currents.
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Ohm's Law is always obeyed.\nIf a conductor is non-linear it has a coefficient of resistance - thermal, pressure, tensile, even voltage-dependent.\nMeasure the current thru it and the voltage across it and you have the instantaneous resistance at the time of measurement.\nThe law stands, but the result may not be static.
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No.  The skin effect will cause the AC resistance to be higher than the DC resistance.  This difference is larger for higher frequencies and for larger wires.
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If you say that C is correct and I agree, this is because in the diagram you see that U is the positive end of the battery,  and thus at a higher potential. V is the negative end and thus less(zero). At W, the potential is same as V because there is no resistance(negligible) in the wire. \nAs R is directly proportional to resistance potential, thus X is at a higher potential. Then, Y is same as X, and Z is higher than Y because of the same reason.
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The entire reason that every house and business and car/truck has breaker boxes is because of resistance. Current flowing where it shouldn't, and causes somehting to heat up is because of resistance!\n\nComputers....same thing. Most circuit boards have relayes that will 'trip' if a short occurs, and usually this results in things getting overheated.......because of resistance.\n\nResistance is like friction for electrons. If you rub two sticks together they get hot (resistance)....same for electrons flowing thru a wire. The electrons 'bump' into various things as they go, and it gives rise to heat to put it simply.\n\nToasters rely on resistance to work. Ever look inside when one is on? Ever see the glowing wires in there?.....resistance causes the wires to heat and get red hot! This is what 'cooks' your toast.\n\nSame for an electric oven.......electric heating in your home.\n\nDoes this help?\n\nGood luck to you!\n\n:)
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Electrical resistance is that element of electrical circuit which opposes flow of current through it.\n1.Resistance is dependent on the material.Like wood is insulator(ALMOST infinite resistance).\n2.Resistance of a wire having more cross sectional area is less and less cross sectional area is more(i.e. it is inversely propotional to the cross sectional area.)\n3.It is more for more length and less for less length.\n4. Resistance varies with temprature.For metals like platinum it increses with temprature.
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Remember the equation v/i=r, Keep the voltage constant over all the areas. If the resistance goes up, then the current goes down.\nIf you have zero ohms, you have a short. IF you have infinite resistance, you have a break.  This seems general, but this is a great help for most of the electronics applications you will need. \nIf you want more you will need to give us more info.
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It depends on both the type of current and the circuit.  For example, AC and DC currents passing through a circuit with reactive elements (capacitors and inductors) will much diffreently from one another.... Ohm's law always applies however...
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Standard copper coaxial CABLE TV wires use a drip-loop to compensate.\n\nThe drip loop is approximately 12 inches long, so the wire probably doesn't move more than six inches.
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It doesn't affect it much at all, it is just a chunk of metal inside there. You would have probably just as much affect by adding 10 feet to the run of wire. \n\nUnless the breaker is old and gets hot from the increased resistance anyway. In that case you should replace it and then you will be fine.
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Trick question... all things regardless of weight fall at the same speed. You need to know how big the item is first... this is the only way to calculate resistance.
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You don't lose amps in a wire, you probably mean voltage drop.  The current (amps) going in one end of a wire is the same going out the other end.  The voltage drop is the current times the resistance of the wire.  You can get the resistance from online tables based on wire size.  Use 4000 ft, since you have drop in both directions.  If this were for a 120V extension code for example, if you had a large enough wire that you had 2V of drop in 2000ft, you would have 116V at the other end, since 2V affects each conductor.\n\n2000ft is a really long way to go, depending on what you are doing.
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Well, not everything obeys Ohm's Law (for example, diodes), so it's not really a law.  It is more of a definition of R (resistance) in the sense that IF a system obeys E = I/R then that system has a well-defined resistance, R.
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um, basically, there is no connection between resistance and frequency. there are however some circuits that output a frequency based on a time constant that can be set by a resistor though. if that is what you mean, then we need to know what circuit you are talking about.
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14 guage wire is larger in diameter than 16 guage wire and has a greater current-carrying capacity.\n\nSee http://en.wikipedia.org/wiki/American_wire_gauge
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The length of a bungee cord depends heavily on the length of the drop combined with the weight. So..without the other variable, this question cannot be answered.
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How to Calculate Voltage Drop For Long Paired Wire Runs\n \nA primary concern when installing lengths of wire is voltage drop. The amount of voltage lost between the originating power supply and the device being powered can be significant. Improper selection of wire gauge can lead to an unacceptable voltage drop at load end. The following chart is designed to help calculate voltage drop per 100 feet of paired wire as a function of wire gauge and load current.\n\nBy matching load current (in AMPs) across the top of the chart with wire gauge (AWG) down the left side of the chart, one can determine voltage drop per 100 feet of paired wire run.\n\nNOTE: A paired wire run represents the feed and return line to the load. Therefore, a 500 foot wire pair is equivalent to 1000 feet of total wire.\n\n\nEXAMPLE ONE:\n\nGiven a load current of 1 AMP, and using 18 AWG wire, how much voltage drop can we expect at the load end for a 350 foot run of paired wire?\n\nUsing the chart, we match the row for 18 AWG and the column for 1 AMP and determine that voltage drop per 100 feet is 1.27 Volts. By dividing the paired wire length by 100, we get the factor by which we need to multiply voltage drop per 100 feet to determine total voltage drop. Therefore, 350 feet divided by 100 equals 3.5. Multiply 3.5 by 1.27 volts drop per 100 feet to get your total voltage drop. Thus the total voltage drop is 3.5 times 1.27, or 4.445 voltage drop for 350 feet. \n\nRead more --> http://www.securityideas.com/howtocalvold.html