Q 12-14-027NEETJEE MainEasy
Silicon is doped with a small amount of phosphorus. The resulting crystal, taken as a whole, is
Answer: (B) electrically neutral
Phosphorus (valency 5) adds a free electron, making the crystal n-type. But each phosphorus atom that gives up an electron becomes a positive ion, and every atom added was neutral, so the crystal as a whole stays neutral. "n-type" describes the majority carriers, not the net charge.
Solution by Sreeraj P, M.Sc Physics