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It would be useful to have the exact reference in the text where "correlation" is mentioned, but I would argue that correlation is a word which characterizes the collective behavior of electrons in certain circumstances. Such circumstances are varied, but imply that their behavior (and that may be spatial dynamics, but also spin dynamics or other quantities) ...


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According to my limited understanding of density functional theory. Coulomb interaction is one of the correlation effects. Besides Coulomb interaction, there are interaction due to Pauli exclusion principle and change of kinetic energy compared with that of non-interacting electron gas.


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I have read in a number of places how substances with opposite charges attract each other: The excess electrons in the one substance repels the electrons in the other substance so that they move away from the surface, leaving the protons closer to the surface which are then attracted to the excess electrons in the one surface. Your prescription is ...


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As the previous post mentioned, forget about the concept that the electron is actually spinning. Spin, like rest mass and electric charge, is an intrinsic property of subatomic particles. Yes, it's angular momentum. No, nothing is spinning. Although many physicists today do not like this explanation, special relativity introduces a useful analogy with mass. ...


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Shouldn't the energy gain be greater than this formula describes since the energy from the electric field is applied for so long? The electron gains energy and accelerates until it encounters a collision. This is a statistical process and there's a distribution for the energy loss for many electrons. Then, it can accelerate again from that point on, ...


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First, the electron isn't actually spinning. Physical objects made up of collections of electrons and protons (and neutrons) can have angular momentum because they rotate; the electron does not get its angular momentum for the same reason. Second, the magnetic moment of an object with angular momentum L is proportional to $$ \mu \propto \frac{qL}{M} $$ ...


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What you refer to is probably to ground state of a infinite potential wall. If this is the case, then there, in the ground state, the particles are not localized. You can find the solution of the orthogonal ground-states here: https://en.wikipedia.org/wiki/Infinite_potential_well We can reduce the Problem to a one dimensional case, that doesn't change the ...


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This is really just an extension of Jaskaran's answer, but the answer to your question is yes and here are some examples: if you stroke an unmagnetised piece of metal with a magnet then you can magnetise it (as demonstrated in elementary physics classes across the world!) if you expose magnetised metal to an oscillating magnetic field you can demagnetise ...


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As far as I know magnetic field can be changed by another field. Usually this takes alot of time. Magnetic field would not be changed after it stops interacting with another field. Magnetic field can affect the orientation of domains, and not the spin of electrons. Pardon me if I am wrong.


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If it were possible for one object to pass through another object, then it would be possible for one part of an object to pass through a different part of the same object. Therefore the question asked here is equivalent to the question of why matter is stable. See this question on mathoverflow. That question was more about the stability of individual atoms, ...


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OK to get this all right you should look in a good semiconductor device book, Maybe Ben Streetmans "Solid State Electronic Devices". (But I'll wing it.) To understand PN diodes we break the current up into two pieces. The drift current due to the built in electric field in the depletion region. and the diffusion current (about which you are asking.) The ...


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When we derive Ohm's Law using the Drude Model, we assume at one point of time that E=V/L, when is fact, E=dV/dL, unless E is constant, in which case the assumption E=V/L is true. But I don't understand why the electric field in a conductor must be constant as current flows. Generally, the electric field in a conductor does not have to be constant (in ...


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Fleming's right-hand rule applies when a conductor is moving in a magnetic field and the current is induced. However, in this case, we have a charged particle moving through a non-varying magnetic field, so it's Lorentz magnetic force law that applies best here. The simple form, in which there is only a magnetic field component (and no externally applied ...


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Things are not empty space. Our classical intuition fails at the quantum level. Matter does not pass through other matter mainly due to the Pauli exclusion principle and due to the electromagnetic repulsion of the electrons. The closer you bring two atoms, i.e. the more the areas of non-zero expectation for their electrons overlap, the stronger will the ...


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You Should consider lorentz force into account with the absence of electric field the lorentz force on electron is given by F = -e(v x B) Visit http://sun.iwu.edu/~gspaldin/B_deflection_Lab.pdf


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An easy way to prove Ohm's law for electric fields that aren't constant is to first assume that the electric field is approximately constant over short lengths, just like $E=dV/dL$ suggests. Using that, you can derive Ohm's law for short lengths of material, $dV=IdR$. We'll assume that "current in = current out", which is true at steady-state. This allows us ...


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electricity is the flow of electrons Electricity is about a dozen different things, one of which is the flow of charge-carriers, which in metals is a flow of electrons. It's actually a slow drift of free electrons which are quickly jiggling in random directions. how many electrons are moving in the flow if the flow is 5 V or 12 V Voltage isn't a ...


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An electric circuit is formed when a conductive path is created to allow free electrons to continuously move. This continuous movement of free electrons through the conductors of a circuit is called a current The Volt (V) is a unit for measuring both electric potential difference and electromotive force. The voltage supplied by most automobile storage ...


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Throughout this I will be comparing an electric circuit to a ball falling down an incline. and giving the corresponding analogies. 1) The voltage difference is the difference in potential between 2 points. In the case of the ball, the gravitational potential is proportional to the difference in height between the beginning and end point of the incline. In ...


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For starters, when we talk about voltage as energy per unit charge, is this energy manifest simply as the kinetic energy of the electron? No, not at all. Recall that, in electric circuits especially, voltage is not measured at a point (in general, the potential at a point is not physically meaningful - only the difference in potential of two points ...


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For starters, when we talk about voltage as energy per unit charge, is this energy manifest simply as the kinetic energy of the electron? Voltage is potential energy per unit charge. An analogy: voltage is to charge as altitude (as on the surface of Earth) is to mass. So if you lift a 1kg rock off the ground by a height of 1m, you've added some ...


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Do not equate potential with kinetic energy. How fast electrons flow in a conductor has very little to do with their potential. You need to consider the current and the charge carrier density for that. Depending on the material you can have a few fast electrons or many more slower ones. In semiconductors the carrier velocity will be higher - which is why the ...


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If there was nothing in the way then an electron leaving the anode of a 4 volt battery would have a kinetic energy of 4 electronvolts by the time it reached the cathode. However the mean free path of electrons in metal wires is exceedingly short so electrons never build up anything like this velocity. The end result is that the electron velocities are ...


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![Might orbitals appear as depicted here][1] [1]: http://i.stack.imgur.com/0MYZ6.jpg This image appeared during a test and impressed me as possibly displaying orbitals or energy fluxes generated by them.


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In Bohr`s model postulates are 1.Electrons in atoms orbit the nucleus. 2.The electrons can only orbit stably, without radiating, in certain orbits (called by Bohr the "stationary orbits") at a certain discrete set of distances from the nucleus. These orbits are associated with definite energies and are also called energy shells or energy levels. In these ...


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Due to length contraction, the bunch will appear shorter in the lab frame than it would in its own reference frame. Specifically, if the bunch had a length of $L$ in its own frame of reference, in the lab (primed) frame it would have a length of $$ L^\prime = L/\gamma = L \sqrt{1-v^2/c^2}$$ Note that the length is only contracted in the direction of ...


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The other answers here are very good, but are a bit too in-depth for what I believe you're looking for. The simplest way of thinking about resistance is that the current carrying electrons are colliding with the atoms that make up the conductor. By collide I mean the electrons can interact with the atoms via the Coulomb force. The kinetic energy of the ...


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In the classical model of Drude, the resistance come from the choc of the electron with the impurities or with the phonons (waves in the solid), depending on your materiel. The phenomenon of heating up is that you dissipate the energie given par the current by collision with phonon/impurities etc... If you want a quantum description, you should look ...


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As for the question what "really causes resistance": When looking at a solid which has a periodic crystal structure the electrical resistance would hypothetically be zero if the crystal structure would indeed be perfect and the atoms would keep perfectly still at all temperatures. Note that resistance is a measure of how much - well, resistance - there is ...


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A more precise mathematical way of asking your question is: given a (usually unbounded) self-adjoint operator $H$ on a Hilbert space $\mathscr{H}$, am I able to characterize its spectrum? Finding "closed" solutions to the equation you are writing, means finding eigenfunctions of your operator $H$, possibly belonging to the Hilbert space $\mathscr{H}$ (since ...


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No, they can't. The energy an electron needs to be kicked out of its state needs to come in a single chunck, since the energy levels in an atom are quantized. Because for an electron of bound energy $E$ there is almost never a state with $E + 2\mathrm{eV}$, the atoms are unable to absorb visible light. Well, they may be able to absorb visible light on ...


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In principle, it is possible, using, e.g., high-current relativistic electron beams - please see, e.g., the review http://arxiv.org/abs/physics/0409157 . @John Rennie offers reasonable arguments, but the very real problems he mentions can be overcome - I don't have time to describe the specific mechanisms (see the review). In experiments, propagation length ...


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The cathode ray tube has had the air pumped out. Electrons scatter off oxygen and nitrogen molecules so if you fired an electron beam in air it would be scattered in a short distance. The distance would depend on the beam energy, but it's a lot shorter than 100m. The range of electrons from beta radiation in air is around a metre. You could argue that ...


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There is a commonly used analogy for electric circuits called the hydraulic analogy. This imagines the electrons as water and the wires as pipes. The voltage is equivalent to the water pressure and the current is equivalent to the water flow rate. Start with a DC current and imagine the water is doing work by flowing through a water wheel: This is all ...


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At a beach the waves carry energy and momentum from the sea to the shore, even though the water in the waves moves back and forth. It is the same way with alternating current: what matters is the energy flow carried by the electric and magnetic fields, not the movements of the charges.


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If the voltage reverses doesn't the flow of electrons reverse? It depends. If the alternating voltage is across a diode then, no, the current through the diode doesn't (effectively) reverse but is instead unidirectional. However, a genuine alternating current periodically reverses direction - the electric charge 'sloshes' back and forth within the ...


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it is not just that every transition would result in the change of spin this occurs only some times which is explained below Electron Spin The Pauli Exclusion principle states that two electrons in an atom cannot have the same four quantum numbers (n, l, ml, ms) and only two electrons can occupy each orbital where they must have opposite spin states. These ...


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Your question concerning the scaffolding that makes up various metals, in relation to their appearance is a unique one. As far as I know, what determines the appearance of various metals is determined by the demarcation of the atoms that they are composed of. Various material have a statistically higher chance of reflecting the photons of a wide range of ...


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Well, we are not only looking at the electrons of an object when we look at it. What I understood your basic question to be is why we see different objects having different color. Well the reason for that is because different materials are able to reflect only certain frequencies of light. The reason for this is a little more complex. Color in itself is ...


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The colors depend on the frequency of light. Let me explain. In atoms, there are various discrete energy levels that electrons can occupy. A photon that has energy (which remember depends of its frequency) which matches exactly the difference between the electron and the next excited state, will get absorbed by that electron and get excited to the next ...



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