When Cu and Ge are cooled to -150 °C, the resistance of Cu and that of Ge:
Correct answer: D. Decreases, increases
- A. Increases, increases
- B. Decreases, decreases
- C. Increases, decreases
- D. Decreases, increases
Explanation
Copper (Cu) is a conductor, and its resistance decreases as the temperature decreases due to fewer lattice vibrations. Germanium (Ge) is a semiconductor, and its resistance increases as the temperature decreases because fewer charge carriers are thermally excited.
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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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