Identify the correct statements among the following. (A) The number of electrons ($n_e$) is more than the number of holes ($n_h$) in intrinsic conductors. Choose the correct answer from the options given below: |
(A), (B) and (D) only (B) and (C) only (A), (B), (C) and (D) (B), (C) and (D) only |
(B), (C) and (D) only |
The correct answer is Option (4) → (B), (C) and (D) only ✅ Correct statements: (B), (C), (D) (A) ❌ Incorrect: In an intrinsic semiconductor, every electron excited to the conduction band leaves a corresponding hole in the valence band. Hence, $n_e = n_h$ and not $n_e > n_h$. (B) ✅ Correct: Semiconductors exist as both elemental types (such as Si and Ge) and compound types (such as GaAs and CdS), exhibiting similar electrical properties. (C) ✅ Correct: The number of charge carriers in a semiconductor can be controlled by doping it with suitable impurities. Donor impurities produce n-type and acceptor impurities produce p-type semiconductors. (D) ✅ Correct: A hole is an electron vacancy in the valence band that behaves as a positively charged carrier, contributing to current conduction. |