Match Column I with Column II.
| Column I | Column II |
| 1. n-type semiconductor | A. In |
| 2. p-type semiconductor | B. Rectifier |
| 3. p-n junction diode | C. Sb |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 1-C, 2-A, 3-B
The type of an extrinsic semiconductor is set by the valency of the dopant added to Si or Ge. The use of a p-n junction diode follows from its one-way conduction.
1. n-type semiconductor — This matches (C) Sb. Antimony is pentavalent. Four of its electrons form covalent bonds with the neighbouring Si atoms, and the fifth becomes a free electron. So Sb is a donor, and electrons are the majority carriers.
2. p-type semiconductor — This matches (A) In. Indium is trivalent. It bonds with only three Si atoms and leaves a hole in the fourth bond. So In is an acceptor, and holes are the majority carriers.
3. p-n junction diode — This matches (B) Rectifier. A diode passes current only when it is forward biased. So with an alternating voltage applied, it conducts in one half of each cycle. The output is then restricted to one direction.
NCERT (2026-27):
Summary – “8. n-type semiconducting Si or Ge is obtained by doping with pentavalent atoms (donors) like As, Sb, P, etc., while p-type Si or Ge can be obtained by doping with trivalent atom (acceptors) like B, Al, In etc.”
Application of Junction Diode as a Rectifier – “From the V-I characteristic of a junction diode we see that it allows current to pass only when it is forward biased. So if an alternating voltage is applied across a diode the current flows only in that part of the cycle when the diode is forward biased. This property is used to rectify alternating voltages and the circuit used for this purpose is called a rectifier.”