The temperature coefficient of resistivity for a semiconductor such as silicon is
Correct answer: C. negative
- A. positive
- B. zero
- C. negative
- D. always exactly one
Explanation
Heating a semiconductor promotes far more electrons across the energy gap than it adds scattering, so the number of charge carriers rises steeply and resistivity falls, giving a negative coefficient. Metals have a positive coefficient because their carrier number is already fixed and only scattering changes. A thermistor exploits the negative case to measure temperature.
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About Temperature Coefficient of Resistivity
Temperature coefficient of resistivity describes how a material's resistivity changes for each degree change in temperature. Questions use the relation between resistance, temperature and the coefficient, especially for metallic conductors with positive values and semiconductors with negative values. Resistivity is a material property, unlike resistance, which also depends on dimensions.
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