Which of the following materials have a negative temperature coefficient?
Correct answer: A. Germanium and silicon
- A. Germanium and silicon
- B. Germanium and iron
- C. Iron and silicon
- D. Iron and copper
Explanation
Germanium and silicon, which are semiconductors, exhibit a negative temperature coefficient of resistance. This means that their electrical resistance decreases as temperature increases.Here's why:- Germanium and silicon have a negative temperature coefficient because as temperature increases, the vibrations of the atoms (thermal energy) help to excite electrons into the conduction band, increasing conductivity and reducing resistance.- Iron (a metal) has a positive temperature coefficient, meaning its resistance increases with temperature.- Copper (a metal) also has a positive temperature coefficient, meaning its resistance increases with temperature.
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Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
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