Question

Analyze the impact of temperature on the electronic conductivity of metals and semiconductors. Choose the correct statement:

• A. Increasing temperature decreases the conductivity of metals but increases for semiconductors
• B. Increasing temperature increases the conductivity of both metals and semiconductors
• C. Increasing temperature decreases the conductivity of both metals and semiconductors
• D. Increasing temperature increases the conductivity of metals but decreases for semiconductors

Hint:

Temperature rises? Metals lose conductivity, semiconductors gain it. Just remember: electrons scatter in metals, multiply in semiconductors!

Answer 1

The Correct Option is A

Effect of Temperature on Metals:

• In metals, conductivity is primarily due to free electrons.
• As temperature increases, metal atoms vibrate more (increased lattice vibrations).
• These vibrations scatter the electrons more frequently, reducing mobility.
• Hence, electrical conductivity decreases with increasing temperature.

Effect of Temperature on Semiconductors:

• In semiconductors, conductivity depends on the number of charge carriers (electrons and holes).
• Increasing temperature excites more electrons from the valence band to the conduction band.
• This leads to a higher number of free carriers.
• So, electrical conductivity increases with temperature.

Why the Other Options Are Incorrect:

• (B) is wrong: metals show decreased conductivity with temperature.
• (C) is wrong: semiconductors increase in conductivity, not decrease.
• (D) is the reverse of the correct behavior.

Therefore, the correct answer is: Increasing temperature decreases the conductivity of metals but increases for semiconductors.