A piece of copper and other of germanium are cooled from the room temperature to 80 K, then (a) resistance of each will increase (b) resistance of copper will decrease (c) the resistance of copper will increase while that of germanium will decrease (d) the resistance of copper will decrease while that of germanium will increase

Answer: (d). Copper is a metal: cooling reduces lattice vibrations, so its resistance decreases. Germanium is a semiconductor: cooling reduces the number of free carriers, so its resistance increases. So the answer is (d).

A piece of copper and other of germanium are cooled from the room… | NEET 1992 (AIPMT)

Q65NEET 1992 · AIPMTEasy

Intrinsic & Extrinsic Semiconductors

A piece of copper and other of germanium are cooled from the room temperature to $80\text{ K}$ , then

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Answer: (d)

Copper is a metal: cooling reduces lattice vibrations, so its resistance decreases.
Germanium is a semiconductor: cooling reduces the number of free carriers, so its resistance increases.
So the answer is (d).

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Intrinsic & Extrinsic Semiconductors question from NEET 1992 (AIPMT)

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