This is the Section 1 Module 15 of the compiled Electronics Review Materials taken from different sources including but not limited to Electronics books, past Board Exams Questions, Journals and the Internet. This particular reviewer in Electronics Engineering has random Questions and Answers in random topics. Make sure to familiarize each questions to increase the chance of passing the ECE Board Exam.
Electronics Engineering Reviewers: Section 1 Module 15
1. You are told that a certain air conditioner is rated at 500BTU. What is this KwH?
2. The freq.of common household ac in the US is
3. Suppose you double the V in the single DC circuit, and reduce the resistance in half. The current will become
four times as great
4. A resistor is specified as having a value of 68, but is measured with an ohmmeter as 63 ohms. The value is off by :
5. The force between a magnet and a piece of ferromagnetic metal that has not been magnetized.
is never repulsive
6. A relay is connected into a circuit. So that a device gets a signal only when the relay coil carriers current. The relay is
7. Every chemical element has its own unique type of particle called is
8. If the inductance is small
the energy is released slowly
9. Air works well as a dielectric mainly because it
has low losses
10. A phase difference of 180 degree in the circular model represent
11. Shifting the hase of an ac sine wave by 90 degree is the same thing as
moving it to the right or left by ¼ cycle
12. A phase difference of 540 degree would more often be spoken of as
13. A sine wave are in phase opposition. Wave x has a peak amplitude of 4v and wave y has a peak amplitude of 8v. the resultant has a peak amplitude of
4v in phase with wave y
14. If x lead wave y by 45 degree of wave y then,
wave y is 1/8 cycle behind wave x
15. If wave x lags wave y by 1/3 cycle. Then
wave y is 120 degree earlier than x
16. If the resistance R and the XL both vary from zeroth unlimited values but are always in the ratio 3:1 the point in the RL plane for all resulting impedance will fall away.
a ray of unlimited length.
17. A vector is a quantity that has
magnitude and direction
18. In an RL circuit. A as the ratio of Xl to Fc. Xl/Fc decreases, the angle
19. In an purely reactive circuit. The phase angle is
20. If R increases in an RC circuit. But Xc is always 0 then the vector I the RC plane circuit.
always point straight towards the right
21. If the Fc increases in an RC circuit. But the C and freq. are non – 0 and constant, then the vector in the RC plane will
get longer and rotate counterclockwise
22. The impedance vector 0 – j22 represents.
a pure capacitance
23. If the conductor of a coaxial cable is made to have smaller diameter, all other things being equal, what will happen to the Zo of the transmission line?
it will increase
24. When R = 0 in a series RLC circuit. But the net X is not 0 then impedance vector
none of the above
25. Which of the FF. is the most important consideration in a transmission line
minimizing the loss
26. A problem that standing waves can cause is
all of the above
27. Which of the FF. does not increase the loss in a transmission line?
reducing the power output of the source
28. The C bet. The primary and the secondary winding of a transformer can be minimized by
placing the winding on opposite sides of a toroidal core
29. A transformer has a secondary – primary turns ratio of 0.167 the transformer is
step down unit
30. Which of the FF. is false concerning air core versus ferromagnetic cores?
air concentrates the magnetic line of flux
31. If there is reactance at the output of an impedance transformer
there will be an impedance mismatch, no matter what the turns ratio of the transformer
32. Mutual inductance causes the net value of a set of coils to
vary depending on the extent and phase of mutual coupling
33. If R denotes resistance Z denotes absolute value impedance the R/Z is
34. The rate of change (derivative) of a sine wave is itself a wave that
leads the original wave by 90 degree of phase
35. True power is equal to
vector difference of VA and reactive power
36. The reactance of a section of transmission line depends on all of the FF. except
current in the line
37. The term “ semiconductor” arises from
variable conductive properties of some materials
38. The most common semiconductor among the FF. substance is
39. The purpose of doping is to
give a semiconductor material certain properties
40. The current through a transistor depends on
more than one of the above
41. In a common base circuit. The output is taken from the
42. When a JFET is pinched off
dIG/dEG is 0 with no signal
43. Which of the FF. circuit. generally has the greatest gain
44. If a circuit. Has a voltage gain. Amplification factor of 20, then the voltage gain is
45. A diode a capacitor can be used to detect
46. The S+N / N ratio is measure of
47. A receiver that responds to a desired signal, but not to one very nearby in freq. has good
adjacent channel rejection
48. Because of small size of Ics compared with equivalent circuits made from discrete components
higher switching speeds are attainable
49. In the united states, a license is required for
transmitting on amateur radio freq.
50. 1Mb is the same amount of data as
51. The web would probably work fastest for a user in New York at
2:00am local time on a Tuesday
52. The character string [email protected] might represent
an email address
53. A millivolt is
54. A circuit has a complex impedance of 9 + j12. The absolute impedance is
55. An advantage of LEO communication satellite system over a geostationary communications satellite is te fact that.
large, high gain antennas are not required
56. An audio oscillator that uses two amplifiers is cascade, with + feedback from the output of the 2nd stage to the input of the 1st stage is known is as
57. Electron-hole pairs are produced by
58. Ratio of speed between the main memory and vertical memory
59. Wirewound resistor is normally used in:
high power DC
60. What is the cutoff frequency has a high pass filter with constant k?
¼ pi square root of LC
61. What is the atomic no. of germanium?
62. What is the atomic no. of silicon?
63. The valence shell of silicon atom has a number designation of:
64. Produces pulsating or alternating current or voltage:
65. What circuit configuration has the highest input resistance?
66. What process is done in women with no sign of beast cancer?
67. Permanent magnet moving coil is also called as:
68. What is Friction welding?
Solid state welding
69. Maximum rate of change of output voltage of an op-amp:
70. What instrument has deflection whose magnitude of the electrical quantity is measured directly?
71. Carbon zinc cell to produce 24 volts in series:
72. The algebraic sum of the current entering and leaving a node or junction in an electrical circuits zero:
73. Fixed Negative supply regulator used in industry:
74. Controls open-loop cutoff frequency:
75. Valence electrons are:
In the most distant orbit from the nucleus
76. The nucleus of an atom contains:
Proton and neutron
77. Silicon crystal has:
8 valence electron, four shared, four owned
78. Atom is consists of:
1 nucleus, 1 or more proton and electron, and neutron
79. It is a four-arm bridge and used in measuring resistance:
Wheatstone or resistance bridge
80. High frequency resistance welding uses:
81. What is a photoconductive effect?
– An increased conductivity in an illuminated semiconductor junction
82. Why is chloresteric liquid crystal colored?
Because of the slight twist between layers
83. Every known element has a:
unique type of atom
84. Computer literacy consists of the following components: I. awareness II. Knowledge III. interaction
I, II and III
85. Microprocessor-based robotic system works in conjunction with solid state memory devices. What are these devices?
1 to 4
86. If stepper motor has 200 steps per revolution, what is the angle movement of rotor per step?
87. In an inverting amplifier, close-loop gain is calculated by:
The feedback resistance divided by the input resistance
88. A step by step instruction that run a computer:
89. The portion of restricted envelope where the robot usually used in performing its programmed motions:
90. The impedance vector 5 + j0 is:
A pure resistance
91. Each impedance in R + jXL:
all of the choices
92. In semiconductor crystal, atoms are held together by:
all of the choices
93. The current-carrying part of FET, analogous to garden hose:
94. The difference between insulator and semiconductor:
all of the choices
95. In vector diagrams, the length of the vector is the:
96. The energy band where free electron exists:
97. A positive ion is formed when:
a valence electron breaks away from the atom
98. Image reception in super heterodyne receiver is enhanced by:
99. DC voltmeter with low sensitivity gives accurate measurement for:
Low resistance circuit
100. Two waves are 180 degrees out of phase. This is a difference of: