Saturday, 9 February 2013

Electron theory of metals

The electron theory of metals was developed by Drude & Lorentz , so it is also known as Drude-Lorentz theory of metals.This theory says that "A metal crystal consists of positive metal ions whose valence electrons are free to move between the ions as if they equvalent to an electron gas.The crystal is then imagined to be held together by electrostatic forces of attractions between the positvely charged ions and negatively charged electron gas.It is than assumed that the electrons are free to move in every part of the entire crystal"
         The mutual repulsion between negative electrons is ignored to this theory and the potential field due to the positive is assumed to be completely uniform.
         The free electrons in a metal move iso-tropically and move in a particular direction on an application of electric field.Because of elastic collisions,the magnitudes of steady-state current is proportional to the voltage applied provided the temperature of metals remains constant.

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