The World of Semiconductors

Science and Technology · 10 questions

Fundamentals and applications of semiconductor carrier concentration, band gaps, diodes, and transistors.

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1. What property does the controlled addition of impurities to a semiconductor primarily change?

   1. Free charge-carrier concentration
   2. Atomic nuclear charge
   3. Crystal lattice type
   4. Electron's elementary charge
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   A) Free charge-carrier concentration

2. At a nonzero temperature and thermal equilibrium, how do electron and hole concentrations compare in an intrinsic semiconductor?

   1. Higher electron concentration
   2. Zero carrier concentration
   3. Higher hole concentration
   4. Equal concentrations
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   D) Equal concentrations

3. What is the majority charge carrier in P-type silicon?

   1. Excitons
   2. Ionized donor atoms
   3. Holes
   4. Electrons
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   C) Holes

4. The band gap of a semiconductor is the energy difference between which two bands?

   1. The conduction band and core levels
   2. Two conduction sub-bands
   3. Two valence sub-bands
   4. Valence and conduction bands
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   D) Valence and conduction bands

5. What is the majority carrier in the N-type regions of an NPN bipolar transistor?

   1. Excitons
   2. Electrons
   3. Holes
   4. Ionized acceptor atoms
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   B) Electrons

6. What circuit function uses a Zener diode in its reverse-breakdown region?

   1. Frequency multiplication
   2. Magnetic-field sensing
   3. Energy storage
   4. Voltage regulation
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   D) Voltage regulation

7. In an enhancement-mode MOSFET, what mechanism lets the insulated gate control the channel?

   1. Piezoelectric effect
   2. Electric-field effect
   3. Magnetic induction
   4. Thermionic emission
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   B) Electric-field effect

8. What type of semiconductor does phosphorus doping generally create in silicon?

   1. P-type
   2. N-type
   3. Intrinsic semiconductor
   4. Insulator
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   B) N-type

9. For a PN diode to be forward-biased, what must the P region's potential be relative to the N region?

   1. Higher potential
   2. Lower potential
   3. The same potential
   4. Floating potential
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   A) Higher potential

10. Which semiconductor component converts light into an electrical signal?

    1. Zener diode
    2. Tunnel diode
    3. Photodiode
    4. Varactor diode
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    C) Photodiode