Semiconductor Physics MCQ

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Semiconductor Physics MCQ

Semiconductor Physics MCQ, Multiple Choice Questions on Semiconductor Physics, Gate Questions on Semiconductor Physics, Engineering MCQ, Electronics Device & Circuit MCQ, Semiconductor Physics Multiple Choice Questions

Multiple Choice Questions

Q.1. A semiconductor is formed by …….. bonds.

  • covalent
  • electrovalent
  • co-ordinate
  • none of the above

Answer: covalent

Q.2. A semiconductor has …….. temperature coefficient of resistance.

  • positive
  • zero
  • negative
  • none of the above

Answer: negative

Q.3. The most commonly used semiconductor is ……..

  • germanium
  • silicon
  • carbon
  • sulphur

Answer: silicon

Q.4. A semiconductor has generally …….. valence electrons.

  • 2
  • 3
  • 6
  • 4

Answer: 4

Q.5. The resistivity of pure germanium under standard conditions is about ……..

  • 6 × 104 Ω cm
  • 60 Ω cm
  • 3 × 106 Ω cm
  • 6 × 10−4 Ω cm

Answer: 60 Ω cm

Q.6. The resistivity of pure silicon is about ……..

  • 100 Ω cm
  • 6000 Ω cm
  • 3 × 105 Ω cm
  • 1.6 × 10− 8 Ω cm

Answer: 6000 Ω cm

Q.7. When a pure semiconductor is heated, its resistance ……..

  • goes up
  • goes down
  • remains the same
  • cannot say

Answer: goes down

Q.8. The strength of a semiconductor crystal comes from ……..

  • forces between nuclei
  • forces between protons
  • electron-pair bonds
  • none of the above

Answer: electron-pair bonds

Q.9. When a pentavalent impurity is added to a pure semiconductor, it becomes ……..

  • an insulator
  • an intrinsic semiconductor
  • p-type semiconductor
  • n-type semiconductor

Answer: n-type semiconductor

Q.10. Addition of pentavalent impurity to a semiconductor creates many ……..

  • free electrons
  • holes
  • valence electrons
  • bound electrons

Answer: free electrons

Q.11. A pentavalent impurity has …….. valence electrons.

  • 3
  • 5
  • 4
  • 6

Answer: 5

Q.12. An n-type semiconductor is ……..

  • positively charged
  • negatively charged
  • electrically neutral
  • none of the above

Answer: electrically neutral

Q.13. A trivalent impurity has …….. valence electrons.

  • 4
  • 5
  • 6
  • 3

Answer: 3

Q.14. Addition of trivalent impurity to a semiconductor creates many ……..

  • holes
  • free electrons
  • valence electrons
  • bound electrons

Answer: holes

Q.15. A hole in a semiconductor is defined as ……..

  • a free electron
  • the incomplete part of an electron pair bond
  • a free proton
  • a free neutron

Answer: the incomplete part of an electron pair bond

Q.16. The impurity level in an extrinsic semiconductor is about …….. of pure semiconductor.

  • 10 atoms for 108 atoms
  • 1 atom for 108 atoms
  • 1 atom for 104 atoms
  • 1 atom for 100 atoms

Answer: 1 atom for 108 atoms

Q.17. As the doping to a pure semiconductor increases, the bulk resistance of the semiconductor ……..

  • remains the same
  • increases
  • decreases
  • none of the above

Answer: decreases

Q.18. A hole and electron in close proximity would tend to ……..

  • repel each other
  • attract each other
  • have no effect on each other
  • none of the above

Answer: attract each other

Q.19. In a semiconductor, current conduction is due ……..

  • only to holes
  • only to free electrons
  • to holes and free electrons
  • none of the above

Answer: to holes and free electrons

Q.20. The random motion of holes and free electrons due to thermal agitation is called ……..

  • diffusion
  • pressure
  • ionisation
  • none of the above

Answer: diffusion

Q.21. A forward biased pn junction has a resistance of the ……..

  • order of Ω
  • order of kΩ
  • order of MΩ
  • none of the above

Answer: order of Ω

Q.22. The battery connections required to forward bias a pn junction are ……..

  • +ve terminal to p and −ve terminal to n
  • −ve terminal to p and +ve terminal to n
  • −ve terminal to p and −ve terminal to n
  • none of the above

Answer: +ve terminal to p and −ve terminal to n

Q.23. The barrier voltage at a pn junction for germanium is about ……..

  • 3.5 V
  • 3V
  • zero
  • 0.3 V

Answer: 0.3 V

Q.24. In the depletion region of a pn junction, there is a shortage of ……….

  • acceptor ions
  • holes and electrons
  • donor ions
  • none of the above

Answer: holes and electrons

Q.25. A reverse biased pn junction has ……..

  • very narrow depletion layer
  • almost no current
  • very low resistance
  • large current flow

Answer: almost no current

Q.26. A pn junction acts as a ……..

  • controlled switch
  • bidirectional switch
  • unidirectional switch
  • none of the above

Answer: unidirectional switch

Q.27. A reverse biased pn junction has resistance of the……..

  • order of Ω
  • order of kΩ
  • order of MΩ
  • none of the above

Answer: order of MΩ

Q.28. The leakage current across a pn junction is due to ……..

  • minority carriers
  • majority carriers
  • junction capacitance
  • none of the above

Answer: minority carriers

Q.29. When the temperature of an extrinsic semiconductor is increased, the pronounced effect is on ……..

  • junction capacitance
  • minority carriers
  • majority carriers
  • none of the above

Answer: minority carriers

Q.30. With forward bias to a pn junction, the width of depletion layer ……..

  • decreases
  • increases
  • remains the same
  • none of the above

Answer: decreases

Q.31. The leakage current in a pn junction is of the order of ……..

  • A
  • mA
  • kA
  • μA

Answer: μA

Q.32. In an intrinsic semiconductor, the number of free electrons ……..

  • equals the number of holes
  • is greater than the number of holes
  • is less than the number of holes
  • none of the above

Answer: equals the number of holes

Q.33. At room temperature, an intrinsic semiconductor has ……..

  • many holes only
  • a few free electrons and holes
  • many free electrons only
  • no holes or free electrons

Answer: a few free electrons and holes

Q.34. At absolute temperature, an intrinsic semiconductor has ……..

  • a few free electrons
  • many holes
  • many free electrons
  • no holes or free electrons

Answer: no holes or free electrons

Q.35. At room temperature, an intrinsic silicon crystal acts approximately as ……..

  • a battery
  • a conductor
  • an insulator
  • a piece of copper wire

Answer: an insulator

Field-Effect Transistors (FET) MCQ (Part-1)

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