Question

By increasing the temperature, the electrical conductivity of a conductor and a semiconductor,

• A. increases for both
• B. decreases for both
• C. increases and decreases respectively
• D. decreases and increases respectively

Hint:

- Metals: $T \uparrow \Rightarrow \sigma \downarrow$ - Semiconductors: $T \uparrow \Rightarrow \sigma \uparrow$

Answer 1

The Correct Option is D

Concept:
Effect of temperature on conductivity:
• Conductors:
Increase in temperature $\Rightarrow$ increased lattice vibrations $\Rightarrow$ more collisions $\Rightarrow$ resistance increases $\Rightarrow$ conductivity decreases.
• Semiconductors:
Increase in temperature $\Rightarrow$ more charge carriers generated $\Rightarrow$ conductivity increases.

Step 1: Apply concept.

• Conductor $\rightarrow$ conductivity decreases
• Semiconductor $\rightarrow$ conductivity increases

Step 2: Match option.
\[ \text{Correct option is (D)} \]