Question

A piece of copper and another of germanium are cooled from room temperature to 100K. The resistance of

• A. copper decreases and germanium increases
• B. copper increases and germanium decreases
• C. each of them decreases
• D. each of them increases

Hint:

For conductors, resistance increases as temperature decreases, while for semiconductors, the opposite effect is observed.

Answer 1

The Correct Option is B

When a conductor like copper is cooled, its resistance typically increases because the atomic vibrations decrease, leading to reduced mobility of the free electrons. For semiconductors like germanium, its resistance decreases as temperature decreases due to increased charge carrier mobility. Thus, as the temperature is reduced from room temperature to 100K: - The resistance of copper increases. - The resistance of germanium decreases. Thus, the correct option is (B).