Question

Copper and silicon is cooled from 300 K to 60 K, the specific resistance :-

• A. decreases in copper but increase in silicon
• B. increases in copper but decrease in silicon
• C. increase in both
• D. decrease in both

Answer 1

The correct option is A decreases in copper but increase in silicon

The specific resistance or resistivity , $\rho ={\rho }_0(1+\alpha T)$
where $\alpha =$ temperature coefficient of resistivity is positive for metals (copper) and is negative for semiconductor ( silicon). Thus, when cooling , resistivity decreases in copper and increases in silicon.