if you increase current in a conductor by a factor of 4, what will the magnetic feild do?
598602
Since Magnetic field (B) = [K I(dl x r)]/r^3\n\nwhere I = current in the conductor\n      r = distance of the pt. from the conductor where u  want to find the magnetic field\n\nHere dl x r = vector product of small part of L i.e dl and r\n\nSee here that Magnetic field is directly proportional to Current....therefore when we increase the current by a factor of 4, magnetic field will also increase by a factor of 4.
682407
This is done to link the flux produced in one coil with the other one.Each time the current reverses in the first coil the magnetic flux also reverses which if properly linked with the second coil will induce an emf in the second one as the induced emf will produce a magnetic field which opposes the change in the magnetic field due to the first coil.Iron has a high value of relative magnetic permeability.Thus most of the magnetic flux due to the first coil will pass through it.And if a second coil is wound over it the changing flux will pass through that one too.
721433
Edit: Perhaps I should revamp my answer to provide a clearer (actual) answer, that explains exactly what plays a role and, in effect, why I am right. I also added a couple sources you should read (in case you don't believe me ;-).\n\nAs asked at the first source (which has very good information about electric motors), "How can I make the motor spin faster or slower?". The answer is that it has to do with the power of the magnetic field. Because electicity is magnetic, you can either effect the speed by using a more powerful magnet or a more powerfully magnetic electrical current.\n\nTo quote Wikipedia about what a volt is, "The volt is the SI derived unit of electric potential difference". To truly understand what the "electric potential difference" means, you must first better understand the volt. The volt is a measurement of electromotive force (emf) and is just defined in terms of amperes and watts.\n\nAn amp is the constant current which produces a force equal to 2x10^-7N per meter, when travelling across two parellel wires one meter apart. It is one coulomb of charge per second (Q/t). It is a base unit upon which other units of electicity are defined (such as the volt).\nA watt is the unit of power equal to one joule of energy per second (P=W/t).\n\nHmm. Power? Power of a magnetic field? So how can you get more power in your circuit? If your power source is not rated by power output, then you can figure out the power using convertion:\nA=W/V=C/s\n\nIf you want a higher wattage, you can increase the voltage (electrical potential) or the ampage (current) or both. Or you can increase the charge - the amount of electricity (coulombs).\n\nSo the fact remains that voltage is *not* directly related to the speed of a motor. It can be directly converted in a way that makes it useful for that purpose, but any number of other things can be done to increase the power - the real goal you are looking for.\n\nThe answer is a definite "No." and a half-assed "Yes.".\n\n\n---Original Answer---\nNo. You might want to read more about the electric motor ( http://en.wikipedia.org/wiki/Electric_motor ) and magnetic properties of electricity ( http://en.wikipedia.org/wiki/Electromagnetism ). Also see the definitions of volt ( http://en.wikipedia.org/wiki/Volt ), watt ( http://en.wikipedia.org/wiki/Watt ), and amp ( http://en.wikipedia.org/wiki/Ampere ).
919244
If you are using the hall effect switch itself to change the magnetic field, I guess we would need to know what the amperage requirement of the electromagnet is to spec out the part.  \n\nThis answer is also difficult because we don't know the strength of the magnetic field used to trip the switch nor the time which the magnet would be in the switch range nor the distance from the magnet to the switch.\n\nIf you have access to a bunch of reed or hall effect switches, I would suggest trying several to see which one works?\n\nAlso -- a suggestion -- i would use the hall effect switch as a sensor switch only and not try to run it as a direct switch connected to an electromagnet.  Use it to trip a transistor or FET that will, in turn, drive the electromagnet.  \n\nDoes this help?
1161474
You can't. The polarity of a magnet is set. If you screw it up, sorry!
341660
Induction. \n\nWhen you wind a conductive wire into a coil and pass a current through it, you create a magentic field that extends from the coil.  Similarly, if you hold/move a coiled wire in a magnetic field, you "induce" a current flow in the coil.  With AC, there's no need for the coils to move relative to one another. (That's how a transformer works)  The toothbrush base has a coil in it, and the AC coming out of the wall goes through a coil in the base, induces current in the coil in the toothbrush, and that current charges a cell in the handle.\n\n Here are some neat links:\n\nhttp://www.energyquest.ca.gov/how_it_works/transformer.html\n\nhttp://micro.magnet.fsu.edu/electromag/java/faraday2/
660380
It is called induction, and happens because by moving a magnet near a conductor coil, the magnetic field changes generate a potential between the conductor tips, you may also move the coil, while the magnet is fixed.\n\nAlso if you have a coil near a magnet, and you connect the coil to a power source, the magnet will move.... so that is the way the electric motor works, because when a current flows on any conductor, it generates a magnetic field around it..
300310
Any current-carrying wire produces a magnetic field. The intensity of this field is proportional to the amount of current passing through a conductor. The stronger the current... the higher is the magnetic field produced.
78592
Magnetism is simply the movement of charge.  If you take a coiled wire, and put an electrical current through it, you will in effect get a magnet.
347377
At the very basics it has to do with magnetic fields. When a conductor (ie copper wire) is move across (perpendicular to) a magnet-ic field it causes the electrons in the copper wire to move\n\nthis is very basic info and their are other ways like solar cells (due to electron excitment in a different manner)
220810
No equations but this may help.... when an electrical signal is travelling along, for example a piece of copper wire, there will be a field generated aroung the cable, similar to that of a magnet (remember at school we were taught about magnetic fields  with a magnet piece of paper and iron filings)\nWhen a second piece of wire is brought in close proximity to the 1st piece then it will cut the field , and a signal will be induced into the second piece of wire.This is called mutual induction. If a signal is now added to the second wire then the induced signal will either add or detract from it dependant on the phase at the time.... this will happen, also within the 1st piece of wire, as a field is now being generated by a signal supplied to the second wire.\nNow, by twisting the pairs together the field generated by the signal in the wire will be changing direction along its length (positive then negative then positive and so on)thus cancelling any induced signals (could be crosstalk in a speach circuit) out
882906
Well depends on the max load the circuit can handle. If the circuit can sustain a max load of lets say 10 volts and you push 15 to it, the circuit elements will heat up and fry. Of those elements will include inductors, transformers (up and down) logic controllers, resistors, transistors, capacitors, motors, and a multitude of other components. Lets say computer for example, you would fry the CPU and possibly damage all the attached components! Either way it's a bad situation.\n\nJust increasing the the resistance values of the resistors will not prevent damage. The designing of circuit boards isn't a fly by night type of thing. In some cases you can get seriously hurt or waste alot of money so exercise caution. Good luck.
426575
Your question is confusing, but here I go.\n\nTo have zero current the circuit must be open.\nThat will give you the higher voltage.\nNow if you have a capacitor circuit, when you close the circuit will take some time to be zero current, while the capacitor charges.\nIn a inductor circuit the current is not possible to be zero because of the nature of the circuit, but will be near zero .\n\nIn a resistor circuit, the current never will be zero, the energy will become heat.\n\nso what are you trying to answer ???
103677
the phenomenon is called electgromagnetic induction. The incoming signal induces electric current of variying strength in the antenna which is used by the receiving device.
243034
magnetic fields, if moved in the right way, can create electric currents. Those currents could mess with the nucleus and take it from metastable to unstable. All depends on how the magnetic fields are set up and how you change them.
30784
increasing thickness, decreasing temperature, and decreasing length would all reduce the resistance of a metal wire. so the only thing that reduces it by increasing is thickness.\n\na good way to remember this is just to reason it out. if the wire is thicker, current can move more freely and with less resistance then a thinner, more constricted wire. the electrons in the current would have more space to move around.  if you increase temperature, it would cause more resistance, because with temperature, comes heat, and heat just makes more resistance. lower temperatures allow the current to move more freely, which is why superconductors work really well at low temperatures. and length, well the longer the wire is, the more the resistance is going to build up along the whole thing... the electrons are just encountering more resistance because the wire is longer..
814978
The resistance of the filament will increase as it heats up. So you're going to get something called a "transient", which is when the initial value will stabilize (to the working current in this case), after a period of time.\nA lower starting resistance equals a higher starting current.