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Classical free electron theory could not explain many physical properties. In 1928, Sommerfeld developed a new theory applying quantum mechanical concepts and Fermi-Dirac statistics to the free electrons in the metal. This theory is called quantum free electron theory.
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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.
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.
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.
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 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.
What is free electron theory assumptions?
according to classical free electron theory of electronsan atom contains an electrons in its outer most orbits and metal contains such type of atomsfree electrons moves randomly entire the volume of the metal like the gas molecules in containerwhile random motion of moving of electrons they collide with fixed positve ions or wiht themselves and the collisions formation due to collisions is elastic collosion that means there is no loss of energy.
How does electron movement within a metal correspond to a metals malleability?
Electrons move free freely in a metal.
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.
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.
Why are metal conductive?
Lots of free electrons in conduction band. This is commonly referred to as the electron gas.
Why there is no current in a metal in the absence of electric field across it?
free electron hav random motion in all posible
