Question

Which of the following statement is correct? 
- i) Positive temperature coefficient 
- ii) Charge carrier in semiconductor are ions and electrons

• A. Statement i is correct
• B. Statement ii is correct
• C. Both i and ii are correct
• D. Both i and ii are incorrect

Hint:

In materials science, remember that the behavior of semiconductors differs from conductors and insulators. Charge carriers in semiconductors include electrons and holes, while in conductors, free electrons are the main charge carriers.

Answer 1

The Correct Option is C

- i) Positive temperature coefficient: This is correct. Many materials, especially metals, exhibit a positive temperature coefficient, which means their resistance increases with temperature. This is because, as temperature increases, the vibrations of the lattice in the material increase, causing more scattering of electrons, which increases resistance. 
- ii) Charge carriers in semiconductors are ions and electrons: This is also correct. In semiconductors, the charge carriers are electrons in the conduction band and holes in the valence band. Although in solid-state physics, the term "ions" is less commonly used in reference to semiconductor charge carriers, in the case of ionized impurities or ionic crystal structures, ions can contribute to the charge transport. 
Thus, both statements i and ii are correct, and the correct answer is (C).