Multiple Choice Questions Topic Outline
- MCQs in Atom
- MCQs in Materials Used in Electronics
- MCQs in Current in Semiconductors
- MCQs in N-Type and P-Type Semiconductors
- MCQs in The PN Junction
- MCQs in GreenTech Application 1: Solar Power
Begin and Good luck!
1. An atom is made up of
- A) protons.
- B) neutrons.
- C) electrons.
- D) all of the above
2. The maximum number of electrons in each shell of an atom is
- A) 2.
- B) 2n2 where n is the number of the shell.
- C) 4.
- D) 8.
3. An n-type semiconductor material
- A) is intrinsic.
- B) has trivalent impurity atoms added.
- C) has pentavalent impurity atoms added.
- D) requires no doping.
4. A diode conducts when it is forward-biased, and the anode is connected to the __________ through a limiting resistor.
- A) positive supply
- B) negative supply
- C) cathode
- D) anode
5. The wide end arrow on a schematic indicates the __________ of a diode.
- A) ground
- B) direction of electron flow
- C) cathode
- D) anode
6. The term bias in electronics usually means
- A) the value of ac voltage in the signal.
- B) the condition of current through a pn junction.
- C) the value of dc voltages for the device to operate properly.
- D) the status of the diode.
7. Doping of a semiconductor material means
- A) that a glue-type substance is added to hold the material together.
- B) that impurities are added to increase the resistance of the material.
- C) that impurities are added to decrease the resistance of the material.
- D) that all impurities are removed to get pure silicon.
8. The forward voltage across a conducting silicon diode is about
- A) 0.3 V.
- B) 1.7 V.
- C) –0.7 V.
- D) 0.7 V.
9. You have an unknown type of diode in a circuit. You measure the voltage across it and find it to be 0.3 V. The diode might be
- A) a silicon diode.
- B) a germanium diode.
- C) a forward-biased silicon diode.
- D) a reverse-biased germanium diode.
10. A reverse-biased diode has the _____ connected to the positive side of the source, and the _____ connected to the negative side of the source.
- A) cathode, anode
- B) cathode, base
- C) base, anode
- D) anode, cathode
11. The movement of free electrons in a conductor is called
- A) voltage.
- B) current.
- C) recombination.
- D) equilibrium.
12. A silicon diode is forward-biased. You measure the voltage to ground from the anode at _____, and the voltage from the cathode to ground at _____.
- A) 0 V, 0.3 V
- B) 2.3 V, 1.6 V
- C) 1.6 V, 2.3 V
- D) 0.3 V, 0 V
13. There is a small amount of current across the barrier of a reverse-biased diode. This current is called
- A) forward-bias current.
- B) reverse breakdown current.
- C) conventional current.
- D) reverse leakage current.
14. The boundary between p-type material and n-type material is called
- A) a diode.
- B) a reverse-biased diode.
- C) a pn junction.
- D) a forward-biased diode.
15. Reverse breakdown is a condition in which a diode
- A) is subjected to a large reverse voltage.
- B) is reverse-biased and there is a small leakage current.
- C) has no current flowing at all.
- D) is heated up by large amounts of current in the forward direction.
16. As the forward current through a silicon diode increases, the voltage across the diode
- A) increases to a 0.7 V maximum.
- B) decreases.
- C) is relatively constant.
- D) decreases and then increases.
17. Which statement best describes an insulator?
- A) A material with many free electrons.
- B) A material doped to have some free electrons.
- C) A material with few free electrons.
- D) No description fits.
18. As the forward current through a silicon diode increases, the internal resistance
- A) increases.
- B) decreases.
- C) remains the same.
19. A silicon diode measures a low value of resistance with the meter leads in both positions. The trouble, if any, is
- A) the diode is open.
- B) the diode is shorted to ground.
- C) the diode is internally shorted.
- D) the diode is working correctly.
20. Single-element semiconductors are characterized by atoms with ____ valence electrons.
- A) 3
- B) 4
- C) 5
- D) 2
21. Effectively, how many valence electrons are there in each atom within a silicon crystal?
- A) 2
- B) 4
- C) 8
- D) 16
22. What occurs when a conduction-band electron loses energy and falls back into a hole in the valence band?
- A) doping
- B) recombination
- C) generation
- D) none of the above
23. What types of impurity atoms are added to increase the number of conduction-band electrons in intrinsic silicon?
- A) bivalent
- B) octavalent
- C) pentavalent
- D) trivalent
- E) none of the above
24. What factor(s) do(es) the barrier potential of a pn junction depend on?
- A) type of semiconductive material
- B) the amount of doping
- C) the temperature
- D) all of the above
25. Under normal conditions a diode conducts current when it is
- A) reverse-biased.
- B) forward-biased.
- C) avalanched.
- D) saturated.
26. For a forward-biased diode, as temperature is _____, the forward current _____ for a given value of forward voltage.
- A) decreased, increases
- B) increased, increases
- C) increased, decreases
- D) decreased, decreases
27. For a forward-biased diode, the barrier potential _____ as temperature increases.
- A) decreases
- B) remains constant
- C) increases
28. An ideal diode presents a(n) _____ when reversed-biased and a(n) _____ when forward-biased.
- A) open, short
- B) short, open
- C) open, open
- D) short, short
29. The most common type of diode failure is a(n) _____.
- A) open
- B) short
- C) resistive
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