Explain resistance in terms of electric current.?
114097
casey's last sentence is wrong:\nthe more resistance the slower the flow rate \npressure is determined by voltage\n\njdub says:\n"for example...the higher the voltage, the greater the resistance, and the higher the current, the lower the resistance...etc.."\nshould say_ that a a higher voltage will need a greater resistance to oppose flow in order to keep the current the same, or if you want to raise current you would either raise voltage across given resistance, or lower the resistance at a given voltage.\n\nbrmick says:\nthat air is a better conductor than concrete,\nThis largely depends on the frequency of the source, gases are not generally considered conductive, while concrete which is largely water is a moderate conductor especially if wet or wetted.\nDO this take two light bulbs and wire one of each lamps leads to the other then tie it to its intended source (series) using the remaining leads. check the voltage across the source and between the lamps. Assuming you have two equal size lamps you have {nearly-ignoring impedance} doubled the resistance. and so the current and wattage are cut.
575172
V=IR, voltage = current times resistance. If you know the current flowing in the circuit, just plug that and the known resistance into the formula to get the voltage. If you don't know the current, you need to measure it. One way to measure it is to measure the voltage across the resistor and plug that and the resistance into the equation and calculate it. But if you are measuring the voltage across the resistor, then you don't need to calculate it, do you?
1100598
voltage = current x resistance\nE = I x R  It IS Ohm's law. An easy way to remember the formula and it's configurations is to draw a circle and divide it in half horizontally. Above the line write "E". In the lower half divide the semicircle vertically and write "I" on the left, "R" on the right. It should look something like this:\n                                                     E\n                                                   I    R\nNow just cover up the one you need. and either divide, or multiply.
1170181
If the resistors are in series, then to find the equivalent resistance you just add up all the resistances.  6 + 12 + 18 = 36 Ohms\n\nTo find the current, you take V/R\n\n36 Volts / 36 Ohms  =  1 Ampere\n\nGood job on getting the right answer!
966971
ok resistivity formula is:\n\nresistivity = [resistance x length]/ cross sectional area..\n\nyou didnt give me enough info to work with\n\nhope it helped
315745
There are three main factors which affect the resistance of a wire:\nThe material of the wire. (What the wire is made out of)\nThe length of the wire.\nThe thickness of the wire. (The diameter of the wire)
852862
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.
652086
1. volts\n2. (b) negatively charged.\n3.  short.  Could also be "conductor," but the lack of control seems to indicate an unwanted short.\n4.  watt-hours.\n5.  \n6.  (a) The formula is P=V*V/R.  Where V is the voltage and R is the resistance.  So P=45*45/15=135 watts.  Actually the object is consumming the power, not producing it.\n    (b)  135*10 = 1350 watt-hours, or 1.35 kw-hr.\n    (c) 0.08*1.35 = $1.08\n7.  (a)  V=IR, so if the voltage is increased while the resistance is kept constant, then the current will also increase. (I=V/R)\n    (b)  If the resistance is increased and the voltage is kept constant, then the current has to decrease. (I=V/R)
879048
Resistance = Voltage / Current\n= 1.4/0.8\n= 1.75 ohms.
94961
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.
1095335
As said above but to expand a little a voltage is a potential difference between two points so when the resistance is right and a closed circuit is created the current flows allowing the voltage (potential difference) to be measured.\n\nSee http://en.wikipedia.org/wiki/Voltage\n\nEnjoy, \n\nSi.
1040756
A. 3.3\nThe two parellel resistors receive the same voltage.  Just use ohms law to find the current.  40/12 = 3.3
653976
You need to use Ohm's law.\n  E=I x R  \n  E=Voltage. I=Current/Amps  R=Resistance/Ohms\n  E= 9voltsDC\n  I= 3amperes.\n  R= ?\n  So:\n  R = 9volt/3amp\n  R=  3ohms
739568
Three  terms you need to know are:\n\nVoltage- This is the "potential" to make current flow through \n                a wire.  (measured in volts)\nCurrent- This is the actual electrons or "electricity"  which \n               "flows" through the wire. (measured in amperes or amps)\nResistance- This is the quality of a substance which tends to \n                      allow or inhibit the flow of electricity.\n\nOne more term is power. This is measured in Watts and is \n given as 1 Watt=(1 volt)(1 amp)\n\nHere's how it works.  You put a voltage across a wire.\nYou decide the voltage.  It does not change.  The wire and bulb has "resistance" and only lets a certain amount or current flow.  The current flows through the bulb and lights the bulb.\n So both 100 watt bulbs and 40 watt bulbs have the same \n120v "voltage".  The difference  is that less current flows through the 40 watt bulb, so it is dimmer.\nRemember that power or "Watts" is current  times voltage.\nso lower wattage means lower current.\nThe question should be how much current does each bulb use.\nThe answer is: 100 watt-5/6 amp\n60 watt- 1/2 amp\n40 watt- 1/3 amp
971534
Well, u can assume that on every section of wire there is an amount of current flowing say i1,i2.... etc. and give any direction to them.\nKirchoff has two laws:\n1st law(current law) : At any junction the incoming current is equal to the outgoing current. So at any junction u can add all the incoming currents and equate it to the addition of all outgoing currents.\n2nd law (voltage law) : it states that the total voltage in a closed loop or mesh is zero. so if u consider first loop on left and the direction of current in both sections of wire clockwise. Then u can write -i1R1-i1R2+Ub1=0. if u r tracing the loop in the direction of current then voltage on resistance is negative(-iR) or u can take the vice versa it doesn't matter.For voltage source if the current is moving from positive to negative plate then voltage is termed as positive and the other way negative.\n\nSo form that many number of equation, that suffice u in finding the unknowns. And then by applying simple mathematics find the current in each segment and then the voltage across each resistor. U need to consider here the concept of voltage drop too.
230902
Given Ohm's law of R=V/I or I=V/R, then I is defined by the voltage applied to a conducting material and the resistance that conducting material has in regards to allowing electrons flow from one end to the other. The important point is that the conducting material has a fixed resistance at a given temperature. Meaning resistance is dependant on the enviromental temperature around the material. If we reduce the temperature, conductors tend to allow more electrons to flow and if we increase the temperature the conductor becomes less conducting. This brings us to an important topic - superconductors. As we reach temperatures of absolute zero (-273K). Some conductors exhibit very little resistance at all, if any.
337085
Resistance in a wire is caused by ions in the wire getting in the way of electrons. This causes their drift velocity( the average velocity of an electron) to decrease so current (charge per second)decreases because fewer electrons go past a certain point per second. Things can affect resistance, such as \n-heat as if the wire is hot the ions vibrate more and so get in th way of electrons more, \n-thickness of the wire as when it is thicker there are more spaces for electrons to get through, \n-material of the wire as some is more conductive than others,\nlength of the wire as the longer the wire, the more times the free electrons will collide with other free electrons, and the ions making up the metal. Therefore, more energy is going to be lost in these collisions (as heat). \n try this site http://www.bbc.co.uk/schools/gcsebitesize/physics/electricity_and_magnetism/resistance_and_resistorsrev1.shtml