Semiconductor materials, intrinsic, extrinsic, p-type n-type Quiz 1

 

Semiconductor Materials MCQ Worksheet (CBSE / NEET / JEE)

Practice these 20 multiple choice questions on Semiconductor Materials covering:

• Intrinsic Semiconductors
• Extrinsic Semiconductors
• p-type Semiconductors
• n-type Semiconductors

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Section A: Conceptual Questions

1. The conductivity of an intrinsic semiconductor depends mainly on:
   A) Impurity concentration
   B) Temperature
   C) Pressure
   D) Volume
2. In an intrinsic semiconductor, the number of free electrons is:
   A) Greater than holes
   B) Less than holes
   C) Equal to holes
   D) Zero
3. The forbidden energy gap in semiconductors is typically:
   A) 0 eV
   B) ~1 eV
   C) ~5 eV
   D) Infinite
4. Which of the following is a semiconductor material?
   A) Copper
   B) Silicon
   C) Glass
   D) Rubber
5. Doping a pure semiconductor increases its:
   A) Resistance
   B) Conductivity
   C) Band gap
   D) Mass
6. A pentavalent impurity added to silicon produces:
   A) p-type semiconductor
   B) n-type semiconductor
   C) Intrinsic semiconductor
   D) Insulator
7. In n-type semiconductor, majority charge carriers are:
   A) Holes
   B) Electrons
   C) Protons
   D) Ions
8. The minority carriers in p-type semiconductor are:
   A) Holes
   B) Electrons
   C) Neutrons
   D) Positrons
9. Which impurity is used for making p-type semiconductor?
   A) Phosphorus
   B) Arsenic
   C) Boron
   D) Nitrogen
10. In extrinsic semiconductors, conduction is mainly due to:
    A) Only electrons
    B) Only holes
    C) Majority carriers
    D) Minority carriers

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Section B: Numerical / Application-Based Questions

11. If the temperature of an intrinsic semiconductor increases, its conductivity:
    A) Decreases
    B) Increases
    C) Remains constant
    D) Becomes zero
12. In an intrinsic semiconductor, if electron concentration is 10¹⁶ m^-3, hole concentration is:
    A) 10⁸
    B) 10¹⁶
    C) 10³²
    D) Zero
13. A semiconductor doped with trivalent impurity has:
    A) Excess electrons
    B) Excess holes
    C) Equal carriers
    D) No carriers
14. The donor energy level lies:
    A) Near valence band
    B) Near conduction band
    C) Mid-gap
    D) Outside bands
15. Which has highest conductivity?
    A) Intrinsic semiconductor
    B) p-type semiconductor
    C) n-type semiconductor
    D) Insulator
16. Mobility of electrons compared to holes is:
    A) Less
    B) Equal
    C) Greater
    D) Zero
17. Silicon doped with arsenic becomes:
    A) p-type
    B) n-type
    C) Intrinsic
    D) Insulator
18. The Fermi level in intrinsic semiconductor lies:
    A) Near conduction band
    B) Near valence band
    C) At mid-gap
    D) Outside gap
19. Increasing doping concentration will:
    A) Decrease conductivity
    B) Increase conductivity
    C) Not affect conductivity
    D) Make it insulator
20. In p-type semiconductor, current is mainly due to:
    A) Electrons
    B) Holes
    C) Ions
    D) Neutrons

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Answer Key

Q	Ans	Q	Ans	Q	Ans	Q	Ans
1	B	6	B	11	B	16	C
2	C	7	B	12	B	17	B
3	B	8	B	13	B	18	C
4	B	9	C	14	B	19	B
5	B	10	C	15	C	20	B

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Quick Revision Notes

• Intrinsic semiconductor: Pure material, number of electrons = number of holes
• Extrinsic semiconductor: Doped to increase conductivity
• p-type: Majority carriers are holes (trivalent doping)
• n-type: Majority carriers are electrons (pentavalent doping)
• Key concept: Conductivity increases with temperature and doping