Essay on Physical properties

957 WordsDec 6, 20134 Pages
EGA108 / EG-279 ASSESSED SHEET 1 To be handed in via Blackboard by 5pm on Thurs Nov 8th. Show your workings in all cases – if you want to include hand-written workings, embed these as a scanned or photographed image. e = 1.6 x 10-19 C NA = 6.03 x 1023 me = 9.11 x 10-31 kg kB = 1.38 x 10-23 JK-1 By: darky- 712402 1 List two aspects of materials behaviour that the Drude model can explain. The Drude model can explain the Thermal Conductivity in metals and Electrical Conductivity of metals. List two aspects of materials behaviour that the Drude model can’t explain but the Quantum Free Electron model can. Explains the effects of the temperature, impurities, and deformation on Electrical Conductivity in which the Drude Model…show more content…
b) How the Quantum Free Electron Theory predicts that the conductivity of metals decreases as the temperature increases. In the Quantum Free Electron Theory the electrons are considered as waves, so the electrons will have much similar behaviour to waves. The temperature is related to the heat capacitance. So each element will have different heat capacitance. The Quantum Free Electron predicts that scattering causes electrons to drop back down in Energy. Which means that as the temperature goes down the stability of the electrons will increase; also the amount of electron which can jump into a higher level will decrease thus more stability in the atom. This means better conductivity in lower temperatures. So when the temperature increases, it will cause vibrations that change the lattice, and the lower level electron will get excited to move into a higher level which causes instability in the element. Thus, the conductivity will decrease. c) How the Band Theory predicts that the conductivity of silicon increases as the temperature increases. The band theory gives explanations of how Semiconductors differ from metals because as the temperature increases the conductivity increases. The Band Theory considers that for
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