Answer: Pentavalent impurity (e.g., phosphorus).
- A Trivalent impurity (e.g., boron)
- B Pentavalent impurity (e.g., phosphorus)
- C Both trivalent and pentavalent
- D No impurity
Correct answer: B. Pentavalent impurity (e.g., phosphorus)
Explanation: N-type: doped with pentavalent atoms (5 valence electrons like P, As, Sb). Extra electron becomes majority carrier.
Conductors have overlapping bands, semiconductors have a small energy gap that can be bridged by heat or doping, and insulators have a large gap that blocks conduction.
Concept context
Band theory, p-n junction, diodes, transistors, logic gates, and integrated circuits.