Mobility And Temperature Dependence Of Resistivity Current And Electricity
Concepts to remember on Mobility and temperature dependence of resistivity: Current and Electricity
Key Concepts
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Drift velocity: the average velocity of charge carriers in a conductor.
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Mobility: the measure of how quickly charge carriers move in response to an applied electric field.
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Resistivity: the opposition to the flow of electric current in a material.
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Temperature dependence of resistivity: the change in resistivity of a material with temperature.
Mobility and Resistivity
- Resistivity is inversely proportional to mobility. If the mobility of charge carriers increases, the resistivity decreases, and vice versa.
Temperature dependence of resistivity:
Metals:
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As temperature increases, the thermal vibrations of the metal atoms increase, which interfere with the movement of charge carriers (electrons).
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This increased interference causes the resistivity of the metal to increase with temperature.
Semiconductors:
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As temperature increases, the number of charge carriers (electrons and holes) in a semiconductor increases due to the breaking of covalent bonds.
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The increased number of charge carriers decreases the resistivity of the semiconductor.
Insulators:
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The resistivity of insulators remains relatively constant with temperature changes. They have very few free carriers, and those are bound within atoms.
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The changes in resistivity with temperature are very small and often negligible compared to metals and semiconductors.