Semiconductor MCQ

1. Valency of silicon is

  1. 4
  2. 3
  3. 5
  4. 2
Answer
Answer. a

2. Overlapping of the conduction band and the valence band occurs in

  1. Conductors only
  2. Semiconductors only
  3. Insulator only
  4. Conductors and semiconductors both
Answer
Answer. a

3. The electron-hole mobility ratio in germanium is

  1. 2 : 1
  2. 1 : 1
  3. (2.8) : 1
  4. (1.2) : 1
Answer
Answer. a

4. Compared to Si, GaAs has

  1. higher optoelectronic conversion efficiency
  2. easier to grow crystals since the vapour pressure of arsenic is high
  3. poorer crystal quality since stoichiometric growth is difficult
  4. higher signal speed since electron mobility is higher
  1. Statement II and IV are correct
  2. Statement I and III are correct
  3. Statement I and III are correct
  4. Statement II and III are correct
Answer
Answer. b

5. Consider the following statements about conditions that make a metal-semiconductor contact rectifying

  1. N-type semiconductor with its work function greater than  the work function of the metal
  2. N-type semiconductor with its work function smaller than the work  function of the metal
  3. P-type semiconductor with its work function greater than the work function of the metal
  4. P-type semiconductor with its work function smaller than the  work function of the metal
  1. Statement II and IV are correct
  2. Statement I and IV are correct
  3. Statement I and III are correct
  4. statement II and III are correct
Answer
Answer. c

6. Which material has a negative temperature coefficient?

  1. Brass
  2. Copper
  3. Aluminium
  4. Carbon
Answer
Answer. d

7. If the temperature of a pure silicon specimen is increased then

  1. Only number of free electrons increase
  2. Only number of free holes increase.
  3. Number of free holes and free electrons increases
  4. Only number of free holes decrease
Answer
Answer. c

8. Under thermal equilibrium in a pure semiconductor the ratio of the number of holes to the number of conduction electrons is

  1. 0.5
  2. Infinity
  3. 1
  4. 2
Answer
Answer. c

9. Which of the following materials is a semiconductor?

  1. Chromium
  2. Selenium
  3. Bismuth
  4. Silica
Answer
Answer. b

10. In a semiconductor, the resistivity

  1. Depends on temperature
  2. Depends on voltage
  3. Depends on current through it
  4. None of the above
Answer
Answer. a

11. In the energy level diagram, what is the separation between the conduction band and the valence band?

  1. Forbidden energy gap
  2. Conduction band
  3. Valence band
  4. Energy band
Answer
Answer. a

12. The atomic number of silicon is

  1. 6
  2. 14
  3. 22
  4. 30
Answer
Answer. b

13. The current due to electron flow in the conduction band is

  1. Less than hole current in valence band
  2. Equal to hole current in valence band
  3. Greater than hole current in valence band
  4. Equal to hole current in conduction band
Answer
Answer. c

14. If the atomic number of germanium is 32, the number of electrons in the outermost shell will be

  1. 2
  2. 3
  3. 4
  4. 6
Answer
Answer. c

15. The ratio of reverse resistance and forward resistance of a germanium crystal diode is about

  1. 1 : 1
  2. 100 : 1
  3. 1000 : 1
  4. 40000 : 1
Answer
Answer. d

16. Semiconductor material has

  1. Ionic bonds
  2. Covalent bonds
  3. Mutual bonds
  4. Metallic bonds
Answer
Answer. b

17. A semiconductor when placed at 0 K, will act as

  1. Insulator
  2. Conductor
  3. Semiconductor
  4. Metal
Answer
Answer. a

18. Electronic distribution of a Si atom

  1. 2,10,2
  2. 2,8,4
  3. 2,7,5
  4. 2,4,8
Answer
Answer. b

19. The resistances in the higher range mostly made of

  1. Carbon
  2. Aluminium
  3. Silicon
  4. Germanium
Answer
Answer. a

20. According to free-electron theory, electrons in a metal are subjected to

  1. Constant potential
  2. Sinusoidal potential
  3. Square-wave potential
  4. None-periodic potential
Answer
Answer. a
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