A piece of copper and another of germanium are cooled from room temperature to 77 K, the resistance of (a) copper increases and germanium decreases (b) each of them decreases (c) each of them increases (d) copper decreases and germanium increases

Answer: (d). Copper (metal): fewer lattice vibrations on cooling, so resistance decreases. Germanium (semiconductor): fewer free carriers on cooling, so resistance increases. So the answer is (d).

A piece of copper and another of germanium are cooled from room… | JEE Main 2004 (AIEEE)

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Intrinsic & Extrinsic Semiconductors

A piece of copper and another of germanium are cooled from room temperature to $77\text{ K},$ the resistance of

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Answer: (d)

Copper (metal): fewer lattice vibrations on cooling, so resistance decreases.
Germanium (semiconductor): fewer free carriers on cooling, so resistance increases.
So the answer is (d).

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Intrinsic & Extrinsic Semiconductors question from JEE Main 2004 (AIEEE)

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