Electron flow vs current flow? (Repost)
This force makes the electron current flow from the cathode to the anode. list Cite · link Link What's the difference between speed and velocity? eNotes. An electric current is a flow of electric charge In electric circuits this charge is often carried by The relationship between the voltage (V), resistance (R), and current (I) is . In metallic solids, electric charge flows by means of electrons, from lower to while the chloride ions move towards the positive electrode ( anode). Read 1 answer by scientists to the question asked by Chidambaram T on Aug 19, electron" It means electron flow from -ve (cathode) to +ve terminal ( anode), However, The current flows in the direction opposite to the flow of electrons. . What's the difference between photovoltaic and concentrating solar power?.
However, metal electrode surfaces can cause a region of the vacuum to become conductive by injecting free electrons or ions through either field electron emission or thermionic emission. Thermionic emission occurs when the thermal energy exceeds the metal's work functionwhile field electron emission occurs when the electric field at the surface of the metal is high enough to cause tunnelingwhich results in the ejection of free electrons from the metal into the vacuum.
Externally heated electrodes are often used to generate an electron cloud as in the filament or indirectly heated cathode of vacuum tubes. Cold electrodes can also spontaneously produce electron clouds via thermionic emission when small incandescent regions called cathode spots or anode spots are formed.
These are incandescent regions of the electrode surface that are created by a localized high current. These regions may be initiated by field electron emissionbut are then sustained by localized thermionic emission once a vacuum arc forms. These small electron-emitting regions can form quite rapidly, even explosively, on a metal surface subjected to a high electrical field. Vacuum tubes and sprytrons are some of the electronic switching and amplifying devices based on vacuum conductivity.
Superconductivity Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. Like ferromagnetism and atomic spectral linessuperconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effectthe complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.
The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of perfect conductivity in classical physics. Semiconductor In a semiconductor it is sometimes useful to think of the current as due to the flow of positive " holes " the mobile positive charge carriers that are places where the semiconductor crystal is missing a valence electron. This is the case in a p-type semiconductor. A semiconductor has electrical conductivity intermediate in magnitude between that of a conductor and an insulator.
In the classic crystalline semiconductors, electrons can have energies only within certain bands i. Energetically, these bands are located between the energy of the ground state, the state in which electrons are tightly bound to the atomic nuclei of the material, and the free electron energy, the latter describing the energy required for an electron to escape entirely from the material.9.2 Voltaic cells (SL)
The energy bands each correspond to a large number of discrete quantum states of the electrons, and most of the states with low energy closer to the nucleus are occupied, up to a particular band called the valence band. Semiconductors and insulators are distinguished from metals because the valence band in any given metal is nearly filled with electrons under usual operating conditions, while very few semiconductor or virtually none insulator of them are available in the conduction band, the band immediately above the valence band.
The ease of exciting electrons in the semiconductor from the valence band to the conduction band depends on the band gap between the bands. The size of this energy band gap serves as an arbitrary dividing line roughly 4 eV between semiconductors and insulators.
With covalent bonds, an electron moves by hopping to a neighboring bond. The Pauli exclusion principle requires that the electron be lifted into the higher anti-bonding state of that bond.
In other words, inside the battery plain electrons can't travel around because it takes too much energy to put a plain electron in solution.
Electrons can only travel inside the battery via charged chemicals, ions, which can dissolve off the electrodes.
The chemical reaction is what pushes the electrons inside toward the negative end, because the electrodes at the two ends are made of different materials, which have different chemical stabilities. So overall, electrons flow AROUND the circuit, toward the negative end inside the battery, pushed by the chemical reaction, and toward the positive end in the outside circuit, pushed by the electrical voltage.
Electrical current can flow in the other way in the battery too, if the battery is hooked up to something with a bigger voltage difference a battery charger, for example. Tom and Mike Follow-Up 1: Battery chemistry followup Q: How chemical reaction in a battery pushes the charge to flow in a circuit? Mike W Follow-Up 2: I would have 3 questions: The electrons generated in one type of electrolyte A push those in the conductor like cars bumper-to-bumper when the circuit is closed and thus start traveling from one electrode to the other.
The electrons possess energy - they spin. It is kind of a crazy jumping all around the place within the atom - it almost seems that they are each time in many places. Do they lose that energy over time?
Electric current - Wikipedia
Are there different types of electrons - in respect to their content? That's a challenging, diverse set of questions.
Electrons, like all small things, are indeed fuzzed-out waves, not located in one exact place. The picture of them always hopping around, as if they were first somewhere then somewhere else, is not correct for electrons that have settled in to wave patterns in atoms.
Electron flow vs current flow? (Repost)
However, and this should admittedly sound strange before you learn a little quantum mechanics even in those stable patterns the electrons have some kinetic energy.
More importantly, whether classical or quantum, energy is conserved. The large-scale organized forms of it gradually trickle away into smaller-scale forms, allowing a great diversity of possible states.
That's the implication of second law of thermodynamics. Anyway, all this energy has been around since the Big Bang, as you supposed.