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What else can I help you with?
Why conversion of a photon to an electron positron pair is not possible in free space?
Because energy mass conservation will not be satisfied in free space, so that this process needs some material by which this conversion will be proceed.
Is 'safe' a verb?
No, the word safe is both an adjective and a noun. Adjective: free from danger. Noun: a metal box that valuables are locked inside for safekeeping.
Why electron is the lightest particle?
It's not. There are many particles lighter than electrons. As to why electrons have the mass they do... the first person to figure that out goes on the short list for a free trip to Sweden and a nice medal.
Describe how valence electrons in a metal move?
The characteristic that allows some metals to be better conductors of electricity is that they have 'free electrons'. Free Electrons simply means that there is a weaker bond between the electrons on the outer valence shell to the nucleus of the atom, than other atoms. This weak bond allows electrons in metals to become more easily excited (when mechanical means of generation occurs), where the electrons are able to transfer from one atom to another.I imagine this is what the question is asking. Basically, electricity is inherent in the material. Metals have weak bonds in their outer valence electron shell.A: In metals, the atoms move freely, allowing heat to travel faster. :)
Where do the electrons come from in proton proton chain reaction if hydrogen has only a proton in its atom?
when the 2 Hydrogen nuclei fuse, one of the protons is changed to a neutron via beta + decay, this produces an atom of Deuterium, a positron (beta + particle) and a neutrino. This positron will only travel a short distance before contacting an electron and annihilating each other to convert their masses and kinetic energies into the energy of the photons. The electron is most probably a free electron, as the high temperatures involved in Nuclear fusion would have provided enough energy to ionise electrons from their parent atom.
What is the main difference between Classical free Electron theory and Quantum free Electron theory?
Electrons are fermions and thus cannot occupy the same quantum states. They obey Fermi-Dirac statistics, and will occupy energy levels accordingly. This is different to the classica state where all electrons are pretty much equal (equal energies etc) and are not taken to be distrubuted amongst multiple states and energies. See Fermi Gas Model for a treatment of quantum free electron theory.
What is classical free electron theory of metal?
Classical free electron theory is modeled by drude - Lorentz to explian elctrical conductivity in metals. According to this free electron in a metal (valence electron) move randdomly at room temperature and these free electron are drifted in opposite to the direection of the applied electric field. This is repsonsible for the conduction. Here all the free elctron are are considered as equal in all aspect.
Free-electron theory of metals is used for?
write note on free electron theory
What is free electron theory assumptions?
The free electron theory assumes that electrons in a metal behave like a gas of free particles. It also assumes that these electrons are not restricted to individual atoms, can move freely through the metal lattice, and are responsible for various electrical and thermal properties of metals.
What is the difference between free electron theory and nearly free electron theory?
free electron model not take into account the potential neither the electron interaction. nearly free electron take into account the potential.J.C. Aguiar
Why does the free electron theory fail to predict the semiconducting properties of materials?
Drawbacks of Classical free electron theory:1. It is macroscopic theory2. This theory cannot explain the electron conductivity ofsemiconductors and insulators.3. Ferromagnetism cannot be explained by this theory.4. This theory cannot explain the Photoelectric effect, Comptoneffect and the Black Body radiation.5. The calculated value of specific heat of metals is not matchingwith the experimental value.6. At low temperature, Lorentz number is not a constant. But by12classical theory it is a constant.7. Dual nature cannot be explained.8. Atomic fine spectra cannot be explained.9. Classical theory states that all the free electrons will absorbenergy, but quantum theory states that only few electrons willabsorb energy
What is meant by electronic theory?
Electronic theory is the theory of the behavior of the electron under various conditions including a free electron, a bound electron in either an outer or inner orbit of the atom.
How does electron movement within a metal correspond to a metals malleability?
Electrons move free freely in a metal.
What is the difference between Free Electron Theory and Band Theory of solids?
Free Electron Theory:This theory tells that, metals conduct electricity because of the presence of free electrons in it. The outermost shells of metal atoms will be loosely bound with their nucleus. So the electrons in it are free to move anywhere in the solid.These electrons are called free electrons and they are responsible for the conduction of electricity.Band theory of solids:A solid is assumed to contain many bands in which the electrons in it are packed. The most important are valence band and conduction band. The energy of electrons in these bands will be different.The difference in energies of valence band and conduction band determines whether the solid is a conductor, semi - conductor or insulator.For insulators, the difference between energies of them ( energy gap ) will be very high, and for conductor, these bands overlap each other.The conduction band carries the electrons that conduct electricity, but the valence band has all the electrons in the ground state. Whether they go into the conduction band depends on the temperature and the energy gap between the bands. In a conductor, these bands overlap, and hence many electrons can become conducting. Thus, Band Theory explains distinction between metals and insulators, which Free Electron theory cannot do (since it assumes all valence electrons become conducting). Calculations are be performed to see which materials will have big energy gaps and which will have overlapping bands.
What is sommerfield?
Sommerfield's model is a semi quantum-mechanics, a classical free electron model. However, it differs from the Drude's model since it is incorporate in a quantum mechanics idea such that : - Only discrete energy levels are allowed for the electron. - Together with the Pauli Exclussion Principle and Fermi-Dirac statistic which deal with the probability of occupancy of the energy states by electron. - The density of available states for the electron occupancy.
Why are metal conductive?
Lots of free electrons in conduction band. This is commonly referred to as the electron gas.
What is sommerfield model?
Sommerfield's model is a semi quantum-mechanics, a classical free electron model. However, it differs from the Drude's model since it is incorporate in a quantum mechanics idea such that : - Only discrete energy levels are allowed for the electron. - Together with the Pauli Exclussion Principle and Fermi-Dirac statistic which deal with the probability of occupancy of the energy states by electron. - The density of available states for the electron occupancy.
