InterviewSolution
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InterviewSolution
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Draw a schematic arrangement of Geiger-Marsden experiment showing the scattering of C-particles by a thin foil of gold. Why is it that most of the O-particles go right through the foil and only a small fraction gets scattered at large angles ? |
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Answer» Solution :A schematic arrangement of the Geiger-Marsden EXPERIMENT is shown in Fig. 12.11. In their experiment it was OBSERVED that most of the alpha-particles pass through the gold foil without any appreciable deflection. Some a particles are scattered through different angles and a very small number of particles suffers large angle scattering of about `180^(@)` Large angle scattering can be EXPLAINED if we consider the entire positive CHARGE and almostwhole mass of gold foil atom to be concentrated in a tiny central core of the atom. When an `alpha`-particle with kinetic energy K approaches the gold nucleus DIRECTLY along itscentral line it slows down, as it approaches the a-particles gold nucleus, due to coulombian repulsion force between nucleus and `alpha`-particle. The `alpha` -particle can come up to a certain minimumdistance is calledthe distanceof closed approach . Obviously valueof distanceof closest approach provides the upperlimit onthe size of thenucleus . 
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