You dont have javascript enabled! Please enable it! Electronics Engineering Mastery Test 11: ECE Pre-Board

Electronics Engineering Mastery Test 11: ECE Pre-Board

This is 100 items set of Practice Examination 11 in Electronics Engineering composed of previous and/or potential Board Exams Questions. Read each questions and choices carefully! Choose the best answer. In the actual board, you have to answer 100 items in Electronics Engineering within 4 hours. You have to get at least 70% to pass the subject. Electronics Engineering is 30% of the total 100% Board Rating along with Mathematics (20%), General Engineering and Applied Sciences (20%) and Electronics Systems and Technology (30%).

Start the Test Yourself Exam 11

Choose the letter of the best answer in each questions.

1. A power derating factor of 3.33 mW/ยฐC above 50ยฐC means that

A. you must decrease the DC power dissipation rating by 3.33 mW for every 1ยฐC rise in the operating temperature above 50ยฐC

B. you will end up getting a power of 3.33 mW if temperature goes beyond 50ยฐC

C. you must increase the DC power dissipation rating by 3.33 mW for every 1ยฐC rise in the operating temperature above 50ยฐC

D. your zener diode will dissipate a nominal DC power of 3.33 mW for temperature above 50ยฐC

Solution:

2. When you first turn a power supply on, the filter capacitor initially acts as a short circuit thus creating a high initial current that can possibly destroy your rectifier diodes. What is the best way to limit the said current but without sacrificing the output voltage?

A. use a large-value series current-limiting resistor

B. use large-value filter capacitors

C. use inductive filters instead of capacitive filters

D. donโt turn off your power supply

Solution:

3. The electromagnetic force induced between a varying magnetic field and a stationary conductor.

A. Mutually induced EMF

B. Self-induced EMF

C. Electro statically induced EMF

D. Statically induced EMF

Solution:

4. A wire has a resistance of 5 ฮฉ at room temperature and a temperature coefficient ฮฑ = 4 ร 10-3/ยฐC. Calculate the wire resistance if the temperature rises by 75ยฐC.

A. 6.5 ฮฉ

B. 6.1 ฮฉ

C. 6 ฮฉ

D. 6.16 ฮฉ

Solution:

5. A combination of two charges with equal charge magnitude but opposite signs.

A. magnetic dipole

B. static dipole

C. dynamic dipole

D. electric dipole

Solution:

6. If a dc electromagnetic of 10-V produces a steady-state current of 100-mA in a 100 ฮฉ coil, how much will the current be after 0.2 sec?

A. 63 mA

B. 100 mA

C. 37 mA

D. 200 Ma

Solution:

7. What is the time constant of a 20-H coil having 100 ฮฉ of series resistance?

A. 5 s

B. 0.5 s

C. 0.2 s

D. 20 ms

Solution:

8. If the RC time constant is given to be 1 s, how long will it take for the voltage to drop from 100 V to 50 V?

A. 0.63 s

B. 0.37 s

C. 0.5 s

D. 0.7 s

Solution:

9. The effect of little change in magnetic flux density when magnetic field intensity increases.

A. Retentivity

B. Coercivity

C. Saturation

D. Permeability

Solution:

10. A series resonant circuit at 0.2 MHz develops 100 mV across a 250 ยตH coil with a 2 mV input. Calculate Q.

A. 50

B. 25

C. 100

D. 200

Solution:

11. A point in magnet where the intensity of magnetic lines of force is a maximum.

A. North Pole

B. Saturation Point

C. Coercive point

D. Magnetic pole

Solution:

12. An oscillator circuit that has two capacitors and one inductor on its feedback network

A. Colpitts

B. Clapp

C. Hartley

D. Pierce Crystal

Solution:

13. The ability of a substance of getting magnetized is called

A. Retentivity

B. Permeability

C. Coercivity

D. Susceptibility

Solution:

14. A 12 volt battery is connected to a 5 cm, 350 turn coil with resistance of 15-ฮฉ. What is the field strength produced in Oe?

A. 70

B. 280

C. 56

D. 353

Solution:

15. A magnetic material has a relative permeability of 500. What is the absolute permeability of the material in cgs system?

A. 500

B. 630 H/m

C. 500 G/Oe

D. 630 x 10-6 G/Oe

Solution:

16. The reciprocal of reluctance corresponds to what in electric circuits?

A. Permeance

C. Impedance

D. Conductance

Solution:

17. A material with negative temperature coefficient means

A. Its resistance will increase as temperature increases

B. Its resistance will decrease as temperature decreases

C. Its resistance will increase as temperature decreases

D. Its resistance will decrease as temperature increases

Solution:

18. A 12-V battery with a capacity of 100 A-hr is used to supply 300-W electronic equipment and a 25 W light. How long will this battery last?

A. 7.38 hours

B. 3.69 hours

C. 5.22 hours

D. 2.61 hours

Solution:

19. The physical motion that is due to the forces of magnetic fields

A. Repulsion

B. Attraction

C. Motor Action

D. Rotation

Solution:

20. Which of these statements is FALSE about the relationship of the magnetic force on a moving charge?

A. A magnetic force does not point in the direction of the field or in the direction of the chargeโs velocity

B. A magnetic force is exerted on a moving electric charge

C. No magnetic force is exerted on a charge at rest

D. A magnetic force is exerted on a charge moving along the direction of the magnetic field

Solution:

21. Indicate which of the following statements is FALSE.

A. Capacitive reactance is a measure of the reaction of C to a change in voltage

B. RC time constant is a measure of the reaction of C to a change in voltage

C. The concept of reactance is useful for both sine wave AC circuits and non-sinusoidal waveforms

D. The method of time constant is used to analyze both sinusoidal and non-sinusoidal waveforms

Solution:

22. It is the ability of an insulator to concentrate electric flux

A. Permeability

B. Susceptibility

C. Permittivity

D. Retentivity

Solution:

23. It is commonly used for precision wire-wound resistors, which do not change resistance when the temperature increases

A. carbon

B. aluminum

C. constantan

D. iron

Solution:

24. Which of the following statements is true about the force on a current-carrying straight conductor in a magnetic field?

A. With the conductor at 90ยฐ, the reaction between two magnetic fields is minimum

B. With the conductor at 0ยฐ, there is no effect between them

C. With the conductor is at angle between 0ยฐ and 90ยฐ, only the parallel component is effective

D. A motor action can be produced if the conductor is placed parallel to the magnetic field

Solution:

25. It is known as the breakdown voltage of a dielectric material.

A. relative permittivity

B. dielectric strength

C. velocity reduction ratio

D. velocity factor

Solution:

26. Find the value and tolerance of a resistor having bands of the following: Red, Violet, Green, Silver.

A. 27 Mฮฉ ยฑ10%

B. 2.7 Mฮฉ ยฑ10%

C. 27 kฮฉ ยฑ10%

D. 2.7 kฮฉ ยฑ10%

Solution:

27. Theveninโs theorem replaces a complicated circuit facing a load by an

A. ideal voltage source and parallel resistor

B. ideal voltage source and series resistor

C. ideal current source and parallel resistor

D. ideal current source and series resistor

Solution:

28. In a sine wave AC circuit with inductive reactance, the

A. phase angle of the circuit is always 45ยฐ

B. voltage across the inductance must be 90ยฐ out of phase with the applied voltage

C. current through the inductance lags its induced voltage by 90ยฐ

D. current through the inductance and voltage across it are 180ยฐ out of phase

Solution:

29. What negative feedback type increases both the input and output impedances of an amplifier?

A. Voltage-shunt

B. Current-shunt

C. Voltage-series

D. Current-series

Solution:

30. A linear circuit is one whose parameters (e.g. resistances, etc)

A. change with change in current

B. change with change in voltage

C. do not change with voltage and current

D. are bilateral

Solution:

31. Ten volts is applied across R1, R2, and R3 is series, producing 1 A in the series circuit. R1 equals 6 ฮฉ and R2 equals 2 ฮฉ. Therefore, R3 equals

A. 2 ฮฉ

B. 10 ฮฉ

C. 4 ฮฉ

D. 12 ฮฉ

Solution:

32. A 0.5-C charge is moving at ratio of 5 cm/s. What is the current at 2 sec?

A. 0.25 A

B. 10 A

C. 0.025 A

D. 0.10 A

Solution:

33. The fifth strip of a precision film resistor color code represents

A. tolerance

B. temperature

C. failure rate

D. multiplier

Solution:

34. Find the value of a capacitor in picofarads having the following color bands: Yellow, Violet, Brown, Black, Yellow

A. 47 pF ยฑ10%

B. 470 pF ยฑ10%

C. 47 pF ยฑ20%

D. 470 pF ยฑ20%

Solution:

35. A meter-sensitivity control in a test instrument would probably be:

A. A set of switchable, fixed resistors

B. A linear-taper potentiometer

C. A logarithmic-taper potentiometer

D. A wirewound resistor

Solution:

36. At what temperature a magnetic material will lose its ferromagnetic properties?

A. Curie temperature

B. Absolute temperature

C. ambient temperature

D. room temperature

Solution:

37. What is Coulombโs first law of electrostatics?

A. Like poles repel unlike poles attract each other

B. Like charges repel unlike charges attract each other

C. Unlike poles repel and like poles attract each other

D. Unlike charges repel and like charges attract each other

Solution:

38. A volume control in a stereo compact-disc player would probably be:

A. A set of switchable, fixed resistors

B. A linear-taper potentiometer

C. A logarithmic-taper potentiometer

D. A wirewound resistor

Solution:

39. A conductor in which two oscillating circuit have the same resonant frequency is called

A. Gimmick

B. Synthony

C. Puff

D. Wet contact

Solution:

40. The effect UV radiation that discharges a negatively charged body in a vacuum is called

A. Joule effect

B. Hallwachs effect

C. Hall Effect

D. Joshi effect

Solution:

41. If a wire conductor of 0.1 resistance is doubled in length, its resistance becomes

A. 0.01 โฆ

B. 0.02 โฆ

C. 0.2 โฆ

D. 0.05 โฆ

Solution:

42. On what basis is the size of the filter capacitor selected?

A. short RC time constant

B. power rating

C. voltage rating

D. long RC time constant

Solution:

43. Those magnetic materials are best suited for making armature and transformer cores which have _____ permeability and ______ hysteresis loss.

A. high, high

B. high, low

C. low, low

D. low, high

Solution:

44. A capacitor charged to 100 V and is then switched across a resistor. When the voltage across the capacitor has fallen to 14 V, the duration of the discharge as measured in time constants, is approximately

A. 0.3

B. 2.0

C. 1.0

D. 2.5

Solution:

45. Preventing one material from affecting one another through their common electric or magnetic hysteresis

A. grounding

B. Hall Effect

C. shielding

D. limiting

Solution:

46. If the tolerance color is violet, this means a tolerance of

A. 0.1%

B. 0.5%

C. 0.25%

D. 1%

Solution:

47. A fully charged lead-acid battery will indicate a specific gravity reading between

A. 1.175 to 1.200

B. 1.225 to 1.250

C. 1.200 to 1.225

D. 1.275 to 1.300

Solution:

48. Find the phase angle between the voltages across the current through the circuit when XC is 25 ohms, R is 100 ohms and XL is 100 ohms are in series.

A. 53.1 degrees with the voltage lagging the current

B. 36.9 degrees with the voltage leading the current

C. 53.1 degrees with the voltage leading the current

D. 36.9 degrees with the voltage lagging the current

Solution:

49. For Kirchhoffโs voltage law, circuits are divided into which of the following?

A. Series-parallel circuits

B. Nodes

C. Ohms

D. Loops

Solution:

50. The ability of a conductor to pass or the opposite of resistance?

A. Reactance

B. Capacitance

C. Resistance

D. Conductance

Solution:

51. The resistance of a coil wire increases from 40 ฮฉ at 10ยฐC to 48.25 ฮฉ at 60ยฐC. Find the temperature coefficient at 0ยฐC of the conductor material.

A. 0.0043

B. 0.00493

C. 0.00393

D. 0.0053

Solution:

52. A length of wire has a resistance of 6 ฮฉ. What is the resistance of wire of the same material three times as long as twice the cross-sectional area?

A. 36 ฮฉ

B. 12 ฮฉ

C. 9 ฮฉ

D. 01 ฮฉ

Solution:

53. Which of the following statements is TRUE?

A. An Ideal current source cannot be in parallel with a short circuit

B. An ideal voltage source can be in parallel with an open circuit

C. An ideal current source can be in series with an open circuit

D. An ideal voltage source cannot be in series with an ideal current source

Solution:

54. Halving the cross-sectional area of a conductor will

A. Not affect the resistance

B. Half the resistance

C. Quarter the resistance

D. Double the resistance

Solution:

55. Given a power supply with a full load voltage of 200 volts and a regulation of 25%, what is the no load voltage?

A. 150 volts

B. 240 volts

C. 160 volts

D. 250 volts

Solution:

56. A coil has 6,000 turns of wire and a resistance of 380 ฮฉ. The coil is rewound with the same quantity (weight) of wire, but has 13,400 turns. How many ฮฉ will the new coil have?

A. 1895 ฮฉ

B. 1905 ฮฉ

C. 1825 ฮฉ

D. 1792 ฮฉ

Solution:

57. What is the average power dissipated by an electric heater with resistance of 50 ฮฉ drawing a current of 20 sin 30t A?

A. 0 kW

B. 10 kW

C. 14.14 kW

D. 20 Kw

Solution:

58. Those materials are well suited for making permanent magnets which have ______ retentivity and _____ coercivity.

A. low, low

B. high, high

C. low, high

D. high, low

Solution:

59. A backwards-working electric motor is best described as:

A. An inefficient, energy-wasting device

B. A motor with the voltage connected the wrong way

C. An electric generator

D. A magnetic-field generator

Solution:

60. What measurements are required to determine the phase angle of a single-phase circuit?

A. The power in watts consumed by the circuit

B. The frequency, capacitance and inductance

C. The power in watts, voltage and current

D. The resistance, current and voltage

Solution:

61. An AC circuit consisting of a capacitor, an inductor and a resistor in series is a resonant when the

A. in-phase current equals the out-of-phase current

B. maximum current passes through the circuit

C. power dissipation is minimum

D. power factor is zero

Solution:

62. What is the value of the peak factor for a pure sine wave?

A. 1.414

B. 0.637

C. 0.707

D. 1.11

Solution:

63. The conductance and inductive susceptance of a circuit have the same magnitude. What is the power factor of the circuit?

A. 1

B. 0.707

C. 0.5

D. 0.866

Solution:

64. A circuit has a resonant frequency of 455 KHz and a bandwidth of 57.2 KHz. Find the Q of the circuit.

A. 795

B. 79.5

C. 0.795

D. 7.95

Solution:

65. In a parallel-resonant circuit, what is the relationship between impedance and current?

A. Minimum impedance, minimum current

B. Minimum impedance, maximum current

C. Maximum impedance, minimum current

D. Maximum impedance, maximum current

Solution:

66. A 15 ยตC point charge is located on the y-axis at (0, 0.25). A second charge of 10 ยตC is located on the x-axis at (0.25, 0). If the two charges are separated by air, what is the force between them?

A. 0.0982 N

B. 33.93 N

C. 0.341 N

D. 10.79 N

Solution:

67. A cell connection, providing a higher voltage than a single cell with no increase in current.

A. Ground connected

B. Parallel connected

C. Series connected

D. Series-parallel connected

Solution:

68. A power transforming device, one that converts energy into some other form

A. Converter

B. Transducer

C. Transformer

D. Transmuter

Solution:

69. Refers to charging and discharging of secondary cells?

A. Re-charging of cell

B. Re-aligning of cell

C. Polarizing of cell

D. Cycling of cell

Solution:

70. What static electricity can be produced by rubbing fur on a rubber, amber, or plastic rod?

A. Resinous static electricity

B. Positive static electricity

C. Vitreous static electricity

D. Negative static electricity

Solution:

71. What do you call the space between and around charged bodies?

A. Magnetic field

B. Electromotive force

C. Electromagnetic field

D. Electrostatic field

Solution:

72. In RC circuits, the time constant indicates the time it takes a capacitor to charge up to what percent of the charging voltage?

A. 100%

B. 63%

C. 67%

D. 31%

Solution:

73. A 0.01 m by 0.02m solar cell has a conversion efficiency of 9%. The maximum power rating of the device is

A. 18 mW

B. 180 mW

C. 1800 kW

D. 180 Kw

Solution:

74. A practical type of capacitor used to demonstrate static electricity.

A. Mycalex

. Muller tube

C. Geiger counter

D. Leyden jar

Solution:

75. What does a gold third band represent?

A. 0.01 multiplier

B. 5% tolerance

C. a 10% tolerance

D. a 0.1 multiplier

Solution:

76. What does a fifth band on a resistor indicate?

A. reliability

B. sensitivity

C. life

D. no fifth band

Solution:

77. DC motors and stepper motors are mainly used in robots instead of AC motors because they can

A. be electronically controlled

B. be operated by electric pulses

D. run at varying speed

Solution:

78. The production of hydrogen gas caused by a portion of a charge current breaking down the water in the electrolytes

A. Electrolysis

B. Hydrogenation

C. Hydrolysis

D. Gassing

Solution:

79. Length of twisted two-conductor cable used as a variable capacitive load in which, untwisting and separating the individual conductors vary the capacitance.

A. Gimmick

B. Syntony

C. Puff

D. Wet contact

Solution:

80. The length of cylindrical capacitor is 10mm. The outer diameter of its single core cable conductor is 3 mm surrounded by a paper insulation of outer diameter 6 mm. What is its capacitance?

A. 2.0 ยตF

B. 2.5 ยตF

C. 2.0 pF

D. 2.5 Pf

Solution:

81. What electrical quantity is measured by a watt-hour meter?

A. Current

B. Energy

C. Voltage

D. Power

Solution:

82. The phenomenon whereby current in a gas changes as a result of irradiation by light is called

A. Joule effect

B. Hall Effect

C. Joshi effect

D. Hallwachs Effect

Solution:

83. Three capacitors A, B and C are charged as follows: A = 10 ยตF at 100 V, B = 15 ยตF at 150 V and C = 25 ยตF at 200 V. They are then connected in parallel with terminals of like polarity together. What is the voltage across the combination?

A. 156 V

B. 256 V

C. 165 V

D. 265 V

Solution:

84. A disadvantage of mercury cells and batteries is that:

A. They donโt last as long as other types.

B. They have a flat discharge curve.

C. They pollute the environment.

D. They need to be recharged often.

Solution:

85. How long does it take for an initial charge of 20 VDC to decrease to 0.37 VDC in a 0.01 ยตF capacitor when a 2 Mฮฉ resistor is connected across it?

A. 0.08 second

B. 0.4 second

C. 0.6 second

D. 0.2 second

Solution:

86. If a resistance to which a constant voltage is applied is halved, what power dissipation will result?

A. Doubled

C. Halved

D. Stay the same

Solution:

87. A substance with high retentivity is best suited for making:

A. An ac electromagnet

B. A dc electromagnet

C. An electrostatic shield

D. A permanent magnet

Solution:

88. A significant advantage, in some situations, of a toroidal coil over a solenoid is:

A. The toroid is easier to wind

B. The solenoid cannot carry as much current

C. The toroid is easier to tune

D. The magnetic flux in a toroid is practically all within the core

Solution:

89. The process of converting chemical energy into electrical energy in a cell.

A. Electron flow

B. Electrolysis

C. Polarization

D. Electrochemical action

Solution:

90. The portion of apparent power dissipated in a circuit

A. Phase power

B. True power

C. Power factor

D. Apparent power factor

Solution:

91. Waves in alternating current can involve

A. regular changes in voltages levels

B. regular changes in current levels

C. regular changes in the direction of the electron flow

D. all of the above

Solution:

92. In a triangular or sawtooth waveform, the RMS is how many times the peak value?

A. 0.577

B. 0.500

C. 0.707

D. 0.15

Solution:

93. For an inductor or coil, which of the following indicates how low the losses are?

A. Quality factor

B. Inductive reactance

C. Power factor

D. Impedance

Solution:

94. A certain wire has a resistance R. The resistance of another wire identical with the first except for having twice its diameter is

A. 4R

B. 2R

C. R/2

D. R/4

Solution:

95. Copper is the second best conductor of electricity with ______ free electrons per in3.

A. 1.68 x 1024

B. 1.64 x 1024

C. 1.6 x 1024

D. 1.66 x 1024

Solution:

96. A resistor with the color-coded value of 100 ฮฉ and ยฑ20 percent tolerance can have an actual resistance between

A. 80 and 120 ฮฉ

B. 98 and 102 ฮฉ

C. 90 and 110 ฮฉ

D. 100 and 120 ฮฉ

Solution:

97. What is the basic purpose of all electrical and electronic system that are designed and built?

A. to manipulate information

B. to do work

C. to do work and manipulate information

D. to generate information

Solution:

98. What is the typical leakage resistance of a paper capacitor?

A. 109 ฮฉ

B. 105 ฮฉ

C. 1011 ฮฉ

D. 1010 ฮฉ

Solution:

99. Tantalum electrolytic capacitor has a typical value that ranges from

A. 1 ยตF to 22000 ยตF

B. 5 pF to 1 ยตF

C. 1 ยตF to 1000 ยตF

D. 1 nF to 100 ยตF

Solution:

100. A transformer has 500 turns in the primary and 1500 in the secondary. Assuming no losses, if 45 V is applied to the primary what is the voltage developed in the secondary?

A. 180 V

B. 13.5 V

C. 135 V

D. 90 V

Solution:

Complete List of Electronics Engineering Pre-Board Exams

Electronics Engineering Pre-Board Exams
Module 1: Electronics Engineering Exam 1                   Answer key: EXAM 1
Module 2: Electronics Engineering Exam 2                   Answer key: EXAM 2
Module 3: Electronics Engineering Exam 3                   Answer key: EXAM 3
Module 4: Electronics Engineering Exam 4                   Answer key: EXAM 4
Module 5: Electronics Engineering Exam 5                   Answer key: EXAM 5
Module 6: Electronics Engineering Exam 6                   Answer key: EXAM 6
Module 7: Electronics Engineering Exam 7                   Answer key: EXAM 7
Module 8: Electronics Engineering Exam 8                   Answer key: EXAM 8
Module 9: Electronics Engineering Exam 9                   Answer key: EXAM 9
Module 10: Electronics Engineering Exam 10                   Answer key: EXAM 10

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