Question

When Cu and Ge are cooled to $-{150}^{o}C$ then resistance of Cu .... and that of Ge ....

• A. increases, increases
• B. decrease, increases
• C. decrease, decreases
• D. increases, decreases

Answer 1

The correct option is B decrease, increases

Metals have positive thermal coefficient of resistance while semiconductors have negative thermal coefficient of resistance.

Copper(Cu) is a metal and Germanium(Ge) is the semiconductor. Metals have positive thermal coefficient of resistance while semiconductors have negative thermal coefficient of resistance. Hence, when Cu(metal) is cooled its resistance will decrease with decrease in temperature. And when Ge(semiconductor) is cooled its resistance will increase with decrease in temperature.