This is the Multiple Choice Questions (MCQs) in Chapter 19: Introduction to Semiconductors from the book Teach Yourself Electricity and Electronics, 5th edition by Stan Gibilisco. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.
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1. The term “semiconductor” arises from:
- A. Resistor-like properties of metal oxides.
- B. Variable conductive properties of some materials.
- C. The fact that there’s nothing better to call silicon.
- D. Insulating properties of silicon and GaAs.
2. Which of the following is not an advantage of semiconductor devices over vacuum tubes?
- A. Smaller size.
- B. Lower working voltage.
- C. Lighter weight.
- D. Ability to withstand high voltages.
3. The most common semiconductor among the following substances is:
- A. Germanium.
- B. Galena.
- C. Silicon.
- D. Copper.
4. GaAs is a(n):
- A. Compound.
- B. Element.
- C. Conductor.
- D. Gas.
5. A disadvantage of gallium-arsenide devices is that:
- A. The charge carriers move fast.
- B. The material does not react to ionizing radiation.
- C. It is expensive to produce.
- D. It must be used at high frequencies.
6. Selenium works especially well in:
- A. Photocells.
- B. High-frequency detectors.
- C. Radio-frequency power amplifiers.
- D. Voltage regulators.
7. Of the following, which material allows the lowest forward voltage drop in a diode?
- A. Selenium.
- B. Silicon.
- C. Copper.
- D. Germanium.
8. A CMOS integrated circuit:
- A. Can only work at low frequencies.
- B. Is susceptible to damage by static.
- C. Requires considerable power to function.
- D. Needs very high voltage.
9. The purpose of doping is to:
- A. Make the charge carriers move faster.
- B. Cause holes to flow.
- C. Give a semiconductor material certain properties.
- D. Protect devices from damage in case of transients.
10. A semiconductor material is made into N type by:
- A. Adding an acceptor impurity.
- B. Adding a donor impurity.
- C. Injecting electrons.
- D. Taking electrons away.
11. Which of the following does not result from adding an acceptor impurity?
- A. The material becomes P type.
- B. Current flows mainly in the form of holes.
- C. Most of the carriers have positive electric charge.
- D. The substance has an electron surplus.
12. In a P-type material, electrons are:
- A. Majority carriers.
- B. Minority carriers.
- C. Positively charged.
- D. Entirely absent.
13. Holes flow from:
- A. Minus to plus.
- B. Plus to minus.
- C. P-type to N-type material.
- D. N-type to P-type material.
14. When a P-N junction does not conduct, it is:
- A. Reverse biased.
- B. Forward biased.
- C. Biased past the breaker voltage.
- D. In a state of avalanche effect.
15. Holes flow the opposite way from electrons because:
- A. Charge carriers flow continuously.
- B. Charge carriers are passed from atom to atom.
- C. They have the same polarity.
- D. No! Holes flow in the same direction as electrons.
16. If an electron has a charge of -1 unit, a hole has:
- A. A charge of -1 unit.
- B. No charge.
- C. A charge of +1 unit.
- D. A charge that depends on the semiconductor type.
17. When a P-N junction is reverse-biased, the capacitance depends on all of the following except:
- A. The frequency.
- B. The width of the depletion region.
- C. The cross-sectional area of the junction.
- D. The type of semiconductor material.
18. If the reverse bias exceeds the avalanche voltage in a P-N junction:
- A. The junction will be destroyed.
- B. The junction will insulate; no current will flow.
- C. The junction will conduct current.
- D. The capacitance will become extremely high.
19. Avalanche voltage is routinely exceeded when a P-N junction acts as:
- A. Current rectifier.
- B. Variable resistor.
- C. Variable capacitor.
- D. Voltage regulator.
20. An unimportant factor concerning the frequency at which a P-N junction will work effectively is:
- A. The type of semiconductor material.
- B. The cross-sectional area of the junction.
- C. The reverse current.
- D. The capacitance with reverse bias.