On adding a small amount of boron to a silicon crystal
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → it becomes a p-type semiconductor
Boron has 3 valence electrons. When added to silicon (4 valence electrons), it creates “holes” by accepting electrons from silicon atoms.
Thus, the silicon crystal doped with boron becomes a p-type semiconductor.
Correct option: it becomes a p-type semiconductor