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GMDSS · 605 questions

Element 3 - USCG Exam Questions

General radiotelephone operator knowledge: radio law and regulations, operating procedures, and radio equipment fundamentals.

Every question below is a real U.S. Coast Guard exam question with four choices. Answer one and the correct choice is revealed instantly, with the USCG reference and illustration where the question uses one.

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All Element 3 questions

Questions 1–100 of 605 · page 1 of 7

  1. #1 The product of the readings of an AC voltmeter and AC ammeter is called:
  2. #2 What is the basic unit of electrical power?
  3. #3 What is the term used to express the amount of electrical energy stored in an electrostatic field?
  4. #4 What device is used to store electrical energy in an electrostatic field?
  5. #5 What formula would determine the inductive reactance of a coil if frequency and coil inductance are known?
  6. #6 What is the term for the out-of-phase power associated with inductors and capacitors?
  7. #7 What determines the strength of the magnetic field around a conductor?
  8. #8 What will produce a magnetic field?
  9. #9 When induced currents produce expanding magnetic fields around conductors in a direction that opposes the original magnetic field, this is known as:
  10. #10 The opposition to the creation of magnetic lines of force in a magnetic circuit is known as:
  11. #11 What is the term for the out-of-phase power associated with inductors and capacitors?
  12. #12 What determines the strength of the magnetic field around a conductor?
  13. #13 What will produce a magnetic field?
  14. #14 When induced currents produce expanding magnetic fields around conductors in a direction that opposes the original magnetic field, this is known as:
  15. #15 The opposition to the creation of magnetic lines of force in a magnetic circuit is known as:
  16. #16 What is meant by the term "back EMF"?
  17. #17 Permeability is defined as:
  18. #18 What metal is usually employed as a sacrificial anode for corrosion control purposes?
  19. #19 What is the relative dielectric constant for air?
  20. #20 Which metal object may be least affected by galvanic corrosion when submerged in seawater?
  21. #21 Skin effect is the phenomenon where:
  22. #22 Corrosion resulting from electric current flow between dissimilar metals is called:
  23. #23 Which of these will be most useful for insulation at UHF frequencies?
  24. #24 What formula would calculate the total inductance of inductors in series?
  25. #25 Good conductors with minimum resistance have what type of electrons?
  26. #26 Which of the 4 groups of metals listed below are the best low-resistance conductors?
  27. #27 What is the purpose of a bypass capacitor?
  28. #28 How would you calculate the total capacitance of three capacitors in parallel?
  29. #29 How might you reduce the inductance of an antenna coil?
  30. #30 What are the two most commonly-used specifications for a junction diode?
  31. #31 What limits the maximum forward current in a junction diode?
  32. #32 MOSFETs are manufactured with THIS protective device built into their gate to protect the device from static charges and excessive voltages:
  33. #33 What are the two basic types of junction field-effect transistors?
  34. #34 A common emitter amplifier has:
  35. #35 How does the input impedance of a field-effect transistor compare with that of a bipolar transistor?
  36. #36 An AC ammeter indicates:
  37. #37 By what factor must the voltage of an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the peak voltage value?
  38. #38 What is the RMS voltage at a common household electrical power outlet?
  39. #39 What is the easiest voltage amplitude to measure by viewing a pure sine wave signal on an oscilloscope?
  40. #40 By what factor must the voltage measured in an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the average voltage v...
  41. #41 What is the peak voltage at a common household electrical outlet?
  42. #42 What is a sine wave?
  43. #43 How many degrees are there in one complete sine wave cycle?
  44. #44 What type of wave is made up of sine waves of the fundamental frequency and all the odd harmonics?
  45. #45 What is the description of a square wave?
  46. #46 What type of wave is made up of sine waves at the fundamental frequency and all the harmonics?
  47. #47 What type of wave is characterized by a rise time significantly faster than the fall time (or vice versa)?
  48. #48 What is the term used to identify an AC voltage that would cause the same heating in a resistor as a corresponding value of DC voltage?
  49. #49 What happens to reactive power in a circuit that has both inductors and capacitors?
  50. #50 Halving the cross-sectional area of a conductor will:
  51. #51 Which of the following groups is correct for listing common materials in order of descending conductivity?
  52. #52 How do you compute true power (power dissipated in the circuit) in a circuit where AC voltage and current are out of phase?
  53. #53 Assuming a power source to have a fixed value of internal resistance, maximum power will be transferred to the load when:
  54. #54 What value of series resistor would be needed to obtain a full scale deflection on a 50 microamp DC meter with an applied voltage of 200 volts DC?
  55. #55 Which of the following Ohms Law formulas is incorrect?
  56. #56 If a current of 2 amperes flows through a 50-ohm resistor, what is the voltage across the resistor?
  57. #57 If a 100-ohm resistor is connected across 200 volts, what is the current through the resistor?
  58. #58 If a current of 3 amperes flows through a resistor connected to 90 volts, what is the resistance?
  59. #59 A relay coil has 500 ohms resistance, and operates on 125 mA. What value of resistance should be connected in series with it to operate from 110 V DC?
  60. #60 What is the peak-to-peak RF voltage on the 50 ohm output of a 100 watt transmitter?
  61. #61 What is the maximum DC or RMS voltage that may be connected across a 20 watt, 2000 ohm resistor?
  62. #62 A 500-ohm, 2-watt resistor and a 1500-ohm, 1-watt resistor are connected in parallel. What is the maximum voltage that can be applied across the paral...
  63. #63 In Figure 3B1, what is the voltage drop across R1? illustration
  64. #64 In Figure 3B2, what is the voltage drop across R1? illustration
  65. #65 What is the maximum rated current-carrying capacity of a resistor marked "2000 ohms, 200 watts"?
  66. #66 What is the most the actual transmit frequency could differ from a reading of 462,100,000 Hertz on a frequency counter with a time base accuracy of ±...
  67. #67 The second harmonic of a 380 kHz frequency is:
  68. #68 What is the second harmonic of SSB frequency 4146 kHz?
  69. #69 What is the most the actual transmitter frequency could differ from a reading of 156,520,000 hertz on a frequency counter with a time base accuracy of...
  70. #70 What is the most the actual transmitter frequency could differ from a reading of 156,520,000 Hertz on a frequency counter with a time base accuracy of...
  71. #71 What is the most the actual transmitter frequency could differ from a reading of 462,100,000 hertz on a frequency counter with a time base accuracy of...
  72. #72 At pi/3 radians, what is the amplitude of a sine-wave having a peak value of 5 volts?
  73. #73 At 150 degrees, what is the amplitude of a sine-wave having a peak value of 5 volts?
  74. #74 At 240 degrees, what is the amplitude of a sine-wave having a peak value of 5 volts?
  75. #75 What is the equivalent to the root-mean-square value of an AC voltage?
  76. #76 What is the RMS value of a 340-volt peak-to-peak pure sine wave?
  77. #77 Determine the phase relationship between the two signals shown in Figure 3B3. illustration
  78. #78 What does the power factor equal in an R-L circuit having a 60 degree phase angle between the voltage and the current?
  79. #79 If a resistance to which a constant voltage is applied is halved, what power dissipation will result?
  80. #80 746 watts, corresponding to the lifting of 550 pounds at the rate of one-foot-per-second, is the equivalent of how much horsepower?
  81. #81 In a circuit where the AC voltage and current are out of phase, how can the true power be determined?
  82. #82 What does the power factor equal in an R-L circuit having a 45 degree phase angle between the voltage and the current?
  83. #83 What does the power factor equal in an R-L circuit having a 30 degree phase angle between the voltage and the current?
  84. #84 What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the supply voltage?
  85. #85 What is the meaning of the term time constant of an RC circuit"? The time required to charge the capacitor in the circuit to:"
  86. #86 What is the term for the time required for the current in an RL circuit to build up to 63.2% of the maximum value?
  87. #87 What is the meaning of the term time constant of an RL circuit"? The time required for the:"
  88. #88 After two time constants, the capacitor in an RC circuit is charged to what percentage of the supply voltage?
  89. #89 After two time constants, the capacitor in an RC circuit is discharged to what percentage of the starting voltage?
  90. #90 What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors all in parallel?
  91. #91 What is the time constant of a circuit having two 100-microfarad capacitors and two 470-kilohm resistors all in series?
  92. #92 What is the time constant of a circuit having a 100-microfarad capacitor and a 470-kilohm resistor in series?
  93. #93 What is the time constant of a circuit having a 220-microfarad capacitor and a 1-megohm resistor in parallel?
  94. #94 What is the time constant of a circuit having two 100-microfarad capacitors and two 470-kilohm resistors all in parallel?
  95. #95 What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors all in series?
  96. #96 What is the impedance of a network composed of a 0.1-microhenry inductor in series with a 20-ohm resistor, at 30 MHz? Specify your answer in rectangul...
  97. #97 In rectangular coordinates, what is the impedance of a network composed of a 0.1-microhenry inductor in series with a 30-ohm resistor, at 5 MHz?
  98. #98 In rectangular coordinates, what is the impedance of a network composed of a 10-microhenry inductor in series with a 40-ohm resistor, at 500 MHz?
  99. #99 In rectangular coordinates, what is the impedance of a network composed of a 1.0-millihenry inductor in series with a 200-ohm resistor, at 30 kHz?
  100. #100 In rectangular coordinates, what is the impedance of a network composed of a 0.01-microfarad capacitor in parallel with a 300-ohm resistor, at 50 kHz?

Element 3 questions: what to expect

Q How many Element 3 questions are in the GMDSS pool?

There are 605 Element 3 questions on this site, every one released by the U.S. Coast Guard or taken from the National Maritime Center's sample examinations, with its correct answer. The exam draws its Element 3 module from the same pool.

Q What score do I need to pass the Element 3 module?

Most USCG exam modules, including Element 3, require 70 percent to pass. Rules of the Road modules require 90 percent.

Q Are these the real USCG Element 3 exam questions?

Yes. They are the published U.S. Coast Guard questions, matched to the National Maritime Center's 2026 sample examinations. Answer any question to see the correct choice, the USCG reference and the illustration where the question uses one.

About the GMDSS question pool

These are the published GMDSS Element 3 questions covering general radiotelephone operator knowledge: radio law, operating procedures, and equipment fundamentals.