MULTIPLE CHOICE:

For #1 – 7, refer to the figure below 15. At room temperature, the current in an 29. The valence shell in a copper atom has
intrinsic semiconductor is due the letter designation of
a. holes a. K
b. electrons b. L
c. ions c. M
d. holes and electrons d. N
16. The arrow in the schematic symbol for a 30. Calculate the total current I.
diode points which way?
a. towards the cathode
b. in the direction of the current
flow
c. towards the anode
d. towards magnetic North
17. The average value of a full-wave rectified
1. Calculate I1
voltage with a peak value of 75 V is
a. 6 mA
a. 53 V
b. 7.2 mA
b. 47.8 V
c. 8.6 mA
c. 37.5 V a. 1.207 mA
d. 10 mA
d. 23.9 V b. 2.3404 mA
2. Determine I2
18. A trivalent impurity is added to silicon to c. 2.7809 mA
a. 2.6 mA
create d. 3.001 mA
b. 1.8 mA
a. germanium 31. Holes in an n-type semiconductor are
c. 5.6 mA
b. a p-type semiconductor a. minority carriers that are
d. 8.2 mA
c. an n-type semiconductor thermally produced
3. Find I3
d. a depletion region b. minority carriers that are
a. 0.4 mA
19. Joule/Coulomb is the unit of produced by doping
b. 1.8 mA
a. Electric field potential c. majority carriers that are
c. 2.5 mA
b. Potential thermally produced
d. 8.2 mA
c. Charge d. majority carriers that are
4. Calculate VAB
d. None of the above produced by doping
a. 0.7 V
20. The process of adding an impurity to an 32. The term bias means
b. 1.4 V
intrinsic semiconductor is called a. the ratio of majority carriers to
c. 8.6 V
a. recombination minority carriers
d. 9.3 V
b. ionization b. the amount of current across
5. Determine VBC
c. doping the pn junction
a. 0.7 V
d. crystallization c. a dc voltage that is applied to
b. 1.4 V
21. When a voltmeter is placed across a control the operation of a
c. 8.6 V
forward-biased diode, it will read a device
d. 9.3 V
voltage approximately equal to d. none of the above
6. Determine VCD
a. the bias battery voltage 33. When forward-biased, a diode
a. 0.7 V
b. 0 V a. blocks current
b. 1.4 V
c. the diode barrier potential b. conducts current
c. 8.6 V
d. the total circuit voltage c. has a high resistance
d. 9.3 V
22. Effectively, how many valence electrons d. drops a large voltage
7. Calculate VBD
are there in each atom within a silicon 34. A bismuth atom has ______ valence
a. 0.7 V
crystal? electrons and a boron atom has _____
b. 1.4 V
a. 2 valence electrons.
c. 8.6 V
b. 4 a. 1, 3
d. 9.3 V
c. 8 b. 3, 5
8. A positive ion is formed when
d. 16 c. 5, 3
a. a valence electron breaks away
23. Diode characteristic curve relates d. 5, 1
from the atom
a. VD and time 35. Ion is ________
b. there are more holes than
b. ID and time a. nucleus without protons
electrons in the outer orbit
c. VD and ID b. an atom with unbalanced
c. two atoms bond together
d. Ic and Vce charges
d. an atom gains an extra valence
24. How many electrodes does a pentode c. proton
electron
have? d. free electron
9. The average value of a half-wave
a. 2 36. The name of a pure semiconductor
rectified voltage with a peak value of 200
b. 3 material that has an equal number of
V is
c. 4 electrons and holes
a. 63.7 V
d. 5 a. n-type
b. 127.3 V
25. Three cycles of a sine wave occur in a b. p-type
c. 141 V
time interval of 1/50 second. The c. intrinsic
d. 0 V
frequency of the signal is d. extrinsic
10. The following are some of the basic
a. 50 Hz 37. What is the voltage across a Si diode in
functions within a power supply except
b. 16.67 Hz parallel with a Ge diode whose parallel
a. voltage regulation
c. 150 Hz combination is in series with a 5 V dc
b. rectification
d. 225 Hz source and a 500 Ω resistor? Both anode
c. inverting
26. The current in a semiconductor materials leads are connected to the positive part
d. isolation
are produced by of the supply.
11. When the peak output voltage is 100 V,
a. positive ions a. 0 V
the PIV for each diode in a center-tapped
b. electrons only b. 0.3 V
full-wave rectifier is
c. holes only c. 0.7 V
a. 100 V
d. both electrons and holes d. 5 V
b. 200 V
27. Calculate the total current I. 38. How many electrons are needed in the
c. 141 V
d. 50 V valence orbit to give a material stability?
12. The energy required to change the speed a. 8
of one electron from rest to 0.6 C is b. 4
nearly c. 6
a. .085 MeV d. 2
b. 0.13 MeV 39. A fuse in series with the primary winding
c. 0.26 MeV of the transformer limits the primary
d. 0.37 MeV current to 3 A. If the transformer turns
13. When a 50 Hz sinusoidal voltage is ratio is 1 : 5, what is the maximum
applied to the input of a half-wave a. 1.5 mA permissible value of secondary current?
rectifier, the output frequency is b. 1.8 mA a. 15 A
a. 120 Hz c. 2.0 mA b. 600 mA
b. 30 Hz d. 3.2 mA c. 3 A
c. 50 Hz 28. When an atom gains an additional d. 5 A
d. 0 Hz electron, the result is 40. The reverse current in a diode is the
14. The atomic number of germanium is a. positive ion order of
a. 8 b. negative ion a. μA
b. 2 c. negative molecule b. mA
c. 4 d. negative neutron c. A
d. 32 d. kA
41. What is the maximum efficiency of a full- b. ampere 67. How much is the resistance in a circuit if
wave bridge-type rectifier? c. coulomb 15 V potential difference produces 500
a. 50% d. siemens μA of current?
b. 40.6% 54. The unit of resistance is the a. 30 kΩ
c. 81.2% a. volt b. 3 MΩ
d. 10% b. coulomb c. 300 kΩ
42. This model characterizes the diode as a c. siemens d. 3 kΩ
simple switch that is either closed or d. ohm 68. With R constant
open. 55. What term in electronics is used to a. I and V are inversely
a. ideal express how fast energy is consumed? proportional
b. second approximation a. load b. V and I are directly proportional
c. third approximation b. volt c. V and I are inversely
d. complete c. power proportional
43. If a sine wave voltage varies from 0 – 120 d. conductance d. None of the above
V, how much is its instant voltage at 56. When checked with an ohmmeter, an 69. When a switch is closed it has a total
270°? open resistor measures resistance of
a. 0 V a. infinite resistance a. zero
b. 120 V b. its color-coded values b. 1000 ohms at room
c. -120 V c. zero resistance temperature
d. 141.14 V d. less than its color-coded value c. infinity
44. If one of the diodes in a full-wave bridge 57. With two 45-kΩ resistances in series d. unstable
rectifier opens, calculate the average across a 90-V battery, the voltage across 70. When two or more resistors are
output voltage if the secondary peak each resistance equals connected in series to a battery
voltage is 10 V a. 30 V a. the total voltage across the
a. 5 V b. 45 V combination is the algebraic
b. 7.07 V c. 90 V sum of the voltage across the
c. 3.18 V d. 180 V individual resistors.
d. 6.37 V 58. When one resistance in a series string is b. the same current flows through
45. What is the process by which AC is open, each resistor
converted to pulsating DC? a. the current is maximum in the c. the equivalent resistance of the
a. charging normal resistances combination is equal to the
b. rectification b. the current is zero in all the sum of the resistances of each
c. filtering resistances resistor.
d. clipping c. the voltage is zero across the d. all of the above
46. Electrical classification of material having open resistance 71. The current in an open circuit is
4 valence electrons d. the current increases in the a. normally very high because the
a. insulator voltage source resistance of an open circuit is
b. semiconductor 59. The bigger the diameter of a wire, the 0Ω.
c. conductor ____________ is its resistance. b. usually high enough to blow the
d. compound a. lesser circuit fuse.
e. Septode b. stable c. zero.
47. Determine the voltmeter reading VAB. c. higher d. slightly below normal.
d. unstable 72. If a 10-A and a 3-A flow into a node, how
60. With three 1-kΩ resistances connected in much current must flow away from that
parallel, the combined equivalent node?
resistance equals a. 7 A
a. 0.33 kΩ b. 30 A
b. 1 kΩ c. 13 A
c. 2 kΩ d. this is impossible to determine.
d. 3 kΩ 73. Which of the following is not a valid
61. A 1-Ω resistance in parallel with a 2-Ω expression of Ohm’s Law?
resistance provides a combined a. I = V/R
equivalent resistance of b. R = V/I
a. 3 Ω c. R = PI
a. 20 V b. 1 Ω d. V = IR
b. 19.3 V c. 2 Ω 74. As more resistors are added in series to a
c. -19.3 V d. 0.67 Ω constant voltage source, the power
d. -20 V 62. What is an element in electronics which supplied by the source
48. Determine the voltmeter reading VAB. serves as a protection against overload? a. increases
a. fuse b. decreases
b. semiconductor c. does not change
c. resistor d. increase for a time and then
d. mica starts to decrease
63. A 33-kΩ resistor is connected in series 75. Three resistors of 12, 12, and 6 Ω are
with a parallel combination made up of a connected in parallel. A 12-V battery is
56-kΩ resistor and a 7.8 kΩ resistor. connected to the combination. What is
What is the total combined resistance of the current through the 6-Ω resistor?
these three resistors? a. 1.0 A
a. 39067 Ω b. 2.0 A
b. 63769 Ω c. 3.0 A
a. 10 V c. 95800 Ω d. 4.0 A
b. 1.0 V d. 49069 Ω 76. What is the maximum number of different
c. 9.7 V 64. With two resistances connected in resistance values obtained by using three
d. 9.3 V parallel resistors, if all three need not be used?
49. Electric charge of neutron is the same as a. the current through each must a. 6
a. proton be the same b. 9
b. atom b. the voltage across each must c. 11
c. electron be the same d. 17
d. current c. their combined resistance 77. A carbon composition resistor having only
50. Which of the following is not a good equals the sum of the individual three color stripes has a tolerance of
conductor values a. + 5%
a. copper d. each must have the same b. + 20%
b. silver resistance value c. + 10%
c. glass 65. What is the ohmmeter reading for a short d. + 100%
d. gold circuit? 78. A carbon-film resistor is color-coded with
51. The unit of potential difference is the a. infinite resistance red, violet, black, and gold stripes. What
a. volt b. its color-coded values are its resistance and tolerance?
b. ampere c. zero resistance a. 27 Ω + 5%
c. Siemens d. less than its color-coded value b. 270 Ω + 5%
d. coulomb 66. Three identical resistors are connected in c. 270 Ω + 10%
52. Which of the following statements is true series to a battery. If the current of 12 A d. 27 Ω + 10%
a. unlike charges repel each other flows from the battery, how much current 79. Two 1000-Ω resistors are connected in
b. like charges repel each other flows through any one of the resistors? parallel. Their combined resistance value
c. unlike charges attract each a. 12 A is
other b. 4 A a. 500 Ω
d. both b and c c. 36 A b. 1000 Ω
53. The unit of electric current is the d. zero c. 250 Ω
a. volt
 d. 2000 Ω c. the equivalent resistance of the
80. With the four-band resistor color code, combination is equal to the
gold in the third stripe corresponds to a sum of the resistances of each
a. fractional multiplier of 0.01 resistor.
b. fractional multiplier of 0.1 d. all of the above
c. decimal multiplier of 10 93. The current in an open circuit is
d. resistor tolerance of + 10% a. normally very high because the
81. Ohm’s Law refers to resistance of an open circuit is
a. current is directly proportional 0Ω.
to both voltage and resistance b. usually high enough to blow the
b. power is directly proportional to circuit fuse.
resistance and inversely as the c. zero.
current squared. d. slightly below normal.
c. current varies directly as the 94. Kirchhoff’’s Current Law states that
voltage and inversely as the a. the algebraic sum of the
resistance. currents flowing into any point
d. power is directly proportional to in a circuit must equal zero
both voltage squared and the b. the algebraic sum of the
resistance. currents entering and leaving
82. Reading from left to right, the colored any point in a circuit must equal
bands on a resistor are yellow, violet, zero.
brown, and gold. If the resistor measures c. the algebraic sum of the
513 Ω with an ohmmeter, it is currents flowing away from any
a. well within tolerance point in a circuit must equal
b. out of tolerance zero.
c. right on the money d. the algebraic sum of the
d. close enough to be considered currents around any closed
within the tolerance path must equal zero.
83. Give the color for the number 4. 95. When applying Kirchhoff’s Current Law,
a. red a. consider all currents flowing
b. yellow into a branch point positive and
c. green all currents directed away from
d. blue that point negative.
84. What tolerance does a silver stripe b. consider all currents flowing
represent? into a branch point negative
a. + 1% and all currents directed away
b. + 5% from that point positive.
c. + 10% c. remember that the total of all
d. + 20% the currents entering a branch
85. With resistances of 100, 200, 300, 400, point must always be greater
and 500 Ω in parallel, RT is than the sum of the currents
a. less than 100 Ω leaving that point.
b. more than 1 MΩ d. the algebraic sum of the
c. about 500 Ω currents entering and leaving a
d. about 1 kΩ branch point does not
86. Other factors remaining constant, what necessarily have to be zero.
would be the effect on the current flow in 96. When applying KVL, a closed path is
a given circuit if the applied potential commonly referred to as a
were doubled? a. node
a. It would be reduced by ½. b. principal node
b. It would double. c. loop
c. It would increase 4 times. d. branch point
d. It would remain the same. 97. KVL states that
87. The unit of resistance is the a. the algebraic sum of the
a. volt voltage sources and IR voltage
b. coulomb drops in any closed path must
c. siemens total zero.
d. ohm b. the algebraic sum of the
88. Give the multiplier for red in the third voltage sources and IR voltage
stripe. drops in any closed path can
a. 1 never equal zero.
b. 10 c. the algebraic sum of all the
c. 100 currents flowing around any
d. 1000 closed loop must equal zero.
89. Give R and the tolerance for a resistor d. None of the above.
coded with yellow, violet, brown, and gold 98. When applying KVL,
stripes. a. consider any voltage whose
a. 470 Ω + 5% positive terminal is reached first
b. 47 Ω + 5% as negative and any voltage
c. 4.7 kΩ + 5% whose negative terminal is
d. 47 kΩ + 5% reached first as positive.
90. With two resistances connected in b. always consider all voltage
parallel sources as positive and all
a. the current through each must resistor voltage drops as
be the same negative.
b. the voltage across each must c. consider any voltage whose
be the same negative terminal is reached
c. their combined resistance first as negative and any
equals the sum of the individual voltage whose positive terminal
values is reached first as positive.
d. each must have the same d. always consider all resistor
resistance value voltage drops as positive and
91. What is the total resistance of two equal all voltage sources as negative.
valued resistors in series? 99. The fact that the sum of the resistor
a. the product of both voltage drops equals the applied voltage
b. twice as one in a series circuit is the basis for
c. the difference of both a. KCL
d. the sum of their reciprocal b. node-voltage analysis
92. When two or more resistors are c. KVL
connected in series to a battery d. the method of mesh currents
a. the total voltage across the 100. Determine the voltmeter reading VAB.
combination is the algebraic a. 0 V
sum of the voltage across the b. 10 V
individual resistors. c. 12 V
b. the same current flows through d. -12 V
each resistor