Following is a property of p-type semiconductor
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → The place where the 4th valence electron is missing is called hole
A p-type semiconductor is silicon or germanium doped with a group 13 element, which has only three valence electrons; the missing fourth electron leaves an electron hole, and the holes carry the current as positive charges.
Why the other options are incorrect
Option (1) Each atom forms four covalent bonds — Incorrect. This describes pure silicon; in a p-type crystal the group 13 dopant forms only three bonds.
Option (2) Fifth electron is extra and becomes delocalised — Incorrect. This happens when silicon is doped with a group 15 element (P, As), which gives an n-type semiconductor.
Option (4) Increase in conductivity is due to negatively charged electron — Incorrect. Conduction by extra electrons is also the feature of n-type semiconductors.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Electron-Deficit Impurities
