Is Ohm's law (U = IR)  a law or a definition of R?
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.
501061
The power dissipate in a resistor is P=I^2 * R = V^2/R.\n\nIf many resistors are connected in series, I is the same in each resistor, so P = sum(I^2*R_i) = I^2 * sum(R_i).\nBut V = I * sum(R_i), so P is also = V^2/ sum(R_i).\n\nWhen they are in parallel, they have the same V, so P= sum(V^2/R_i) = V^2*sum(1/R_i). \n\nTherefore, the difference is between sum(1/R_i) and 1/sum(R_i).\n\nIf you still have question, please let us know:\nhttp://www.kodkodkod.com/index_files/submitquestion.htm\n\nKodKodKod Learning Consulting - www.kodkodkod.com
1086143
It's a law of electrical flow along a circuit.
701756
Resistance, R, is converted to conductance, G, by inversion. \nG = 1/R. The unit was called mho (ohm spelled backwards) when I went to school. But the unit name was changed to Siemens (the symbol is S) when the SI unit changes were made. \n\nSo just take all your readings and do a 1/x calculation with your calculator. And put an S after each result for the unit.\n\nIncidentally, ohmmeters are not very accurate with measurements of such low resistance. The test leads probably have resistance of something like .3 ohms.
173205
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.
543978
Frictional force, f = uR\n\nwhere u - frictional constant\n(it is actually "miu", but I can't typr it out.)\n\nand R - the normal/reaction force (which is the reaction caused by the action of the object's weight.)
752024
When you copy and paste these, why don't you convert the "W"s into "ohms"?\n\nHey!  The guy who did your homework for you ("The Great One") gave three WRONG answers (as of 1930 MST 11-14.  He'll probably redo it after he reads this)...heh, heh, heh...
348603
It's a useful tool in electrical network analysis.\n\nAnother one is Kirchoff's law.
653703
The only way to prove this formula is to conduct an experiment. For the theory, recall that current density j is the fundamental quantity in Ohm's law. Also you will require the Boltzmann energy distribution.
1130014
V=IR\n\nWire 1:\n50 = 2 * R1 => R1 is 25 ohms\nCurrent = 2 amps\npower = V*I = 2*50 = 100 watts\n\nWire 2: \n100= 2* R2 => R2 = 50 ohms\nCurrent=2amps\npower = V*I = 100*2 = 200 watts\n\nare you looking for ratios when you say "compare" ?\nif yes: ratio of resistances is  1:2\nratio of currents is 1:1\nand ratio of power is 1:2
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
765323
I am not sure what you mean by "General Gas Laws."  The only law dealt with in physics is the Ideal Gas Law which says that pressure and volume are related to amount of gas, temperature and some constant.\n\nPV = nRT
224197
Amps and volts, while correlated, are different characteristics of electricity. You can determine one from the other, but you can't convert one into the other.\n\nHaving said that, here's OHM's law: \n\nV=I x R, where V is volts, I is Amps and R is resistance.
568661
Let's see if I can remember...\n\na) Find the current flowing through a DC circuit, from a 12V battery and a 3 ohm resistor.\n\nBy Ohm's Law, V = IR, where\n\nResistance = ohms = R\nCurrent = amperes = I\nVoltage = volts = V\n \nYou want to find the current, in amperes, so we switch the equation around a little: if V = IR, that also means that I = V/R (dividing both sides by the same thing gives the same answer).\n\nNow, plug in our values:\nI = (12 volts/ 3 ohms) = 4 amperes\n\nb) what is the current in an AC circuit, with 120 V and 60 W lightbulb.\nIn this case, Watts is a unit of power, and volts is a unit of resistance, and amperes is a unit of current. Electrical power is amperes times volts, or W = I * V\n\nIn this case, W = 60 and V = 120, so we rearrange it:\nW = I * V or \nI = W/V or \nI = (60 watts/120 volts) = 0.5 A\n\nAs for the atom model problem...hmmm! Si is the symbol for silicon. It has an atomic number of 14 (not 16) and an atomic mass of 28.085. According to the Bohr model of an atom, every atom has electrons (with no mass, and a negative charge), protons (with a mass, and a positive charge) and neutrons (with a mass, and no charge). The number of protons and electrons must be equal in order for the atom to have no charge, if one is greater than the other, it results in an ion (positive ion if protons are greater than electrons, negative ion if electrons are greater than protons). Electrons orbit around a nucleus of protons and neutrons.\n\nNow, an element's atomic number (14 in this case) is the same as the number of protons (and electrons, since the element is not an ion, in this case). So a silicon atom has 14 electrons orbiting around its nucleus, and its nucleus also has 14 protons and a number of neutrons.\n\nThe electrons orbit in shells around the nucleus. In the case of silicon, the inner shell has two electrons, the next shell has the maximum number possible or eight, and the third shell has the other electrons, or four. (To check, 2+8+4 = 14.) \n\nFinally, the number of neutrons in the nucleus can be calculated if we know how much a neutron weighs and how much a proton weighs. If N is the weight of a neutron, and P is the weight of a proton, and the number of neutrons is n1, and the number of protons is n2, and we say that the atomic weight is A, we have:\n\nA = (n1 * N) + (n2 * P)\n\nWe want to find n1, so we rearrange this like:\n(n1 * N) + (n2 * P) = A\n(n1 * N) = A - (n2 * P)\nn1 = (A - (n2 * P))/N\n\nNow all we have to do is plug in the relevant values, and we shall get the number of neutrons in an atom of silicon:\nA = 28.085\nn2 = 14\nP = \nN = \n\nSo, n1 = (A - (n2 * P))/N = \n\nSimple! Or at least, simpler! :)\n\nI know what you're going through...getting back into the swing of things after you've been away from school for a long time can be a pain. But keep on plugging away, it's worth it in the end! Good luck!
898015
Nominal= 36ohms\nTolerance=5% \nMultiply nominal by .05 , then add that figure to nominal for Max,.subtract it from nominal for Min.,,and study your ohm's LAW!! ;-)=
315859
you got Ohm law : Ur=R*i(where i stands for current) and what's more, for the coil we have Ul=-L*di/dt . And for the condenser we have C*Uc=q and i = dq/dt.Now you have a differential equation with only one variable i.\n note: if the circuit is parallel then U should be a constant , in this case you shuold use U instead of i.Goodluck
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.