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General exam G5: Electrical Principles

All 40 questions in subelement G5. The exam asks 3 of them, one from each group (G5A, G5B, G5C). Answers are hidden until you open them.

Drill these 40 questions Full practice exam

G5A

  1. G5A01 What happens when inductive and capacitive reactance are equal in a series LC circuit?

    1. Resonance causes impedance to be very high
    2. Impedance is equal to the geometric mean of the inductance and capacitance
    3. Resonance causes impedance to be very low
    4. Impedance is equal to the arithmetic mean of the inductance and capacitance
    Show answer

    C. Resonance causes impedance to be very low

  2. G5A02 What is reactance?

    1. Opposition to the flow of direct current caused by resistance
    2. Opposition to the flow of alternating current caused by capacitance or inductance
    3. Reinforcement of the flow of direct current caused by resistance
    4. Reinforcement of the flow of alternating current caused by capacitance or inductance
    Show answer

    B. Opposition to the flow of alternating current caused by capacitance or inductance

  3. G5A03 Which of the following is opposition to the flow of alternating current in an inductor?

    1. Conductance
    2. Reluctance
    3. Admittance
    4. Reactance
    Show answer

    D. Reactance

  4. G5A04 Which of the following is opposition to the flow of alternating current in a capacitor?

    1. Conductance
    2. Reluctance
    3. Reactance
    4. Admittance
    Show answer

    C. Reactance

  5. G5A05 How does an inductor react to AC?

    1. As the frequency of the applied AC increases, the reactance decreases
    2. As the amplitude of the applied AC increases, the reactance increases
    3. As the amplitude of the applied AC increases, the reactance decreases
    4. As the frequency of the applied AC increases, the reactance increases
    Show answer

    D. As the frequency of the applied AC increases, the reactance increases

  6. G5A06 How does a capacitor react to AC?

    1. As the frequency of the applied AC increases, the reactance decreases
    2. As the frequency of the applied AC increases, the reactance increases
    3. As the amplitude of the applied AC increases, the reactance increases
    4. As the amplitude of the applied AC increases, the reactance decreases
    Show answer

    A. As the frequency of the applied AC increases, the reactance decreases

  7. G5A07 What is the term for the inverse of impedance?

    1. Conductance
    2. Susceptance
    3. Reluctance
    4. Admittance
    Show answer

    D. Admittance

  8. G5A08 What is impedance?

    1. The ratio of current to voltage
    2. The product of current and voltage
    3. The ratio of voltage to current
    4. The product of current and reactance
    Show answer

    C. The ratio of voltage to current

  9. G5A09 What unit is used to measure reactance?

    1. Farad
    2. Ohm
    3. Ampere
    4. Siemens
    Show answer

    B. Ohm

  10. G5A10 Which of the following devices can be used for impedance matching at radio frequencies?

    1. A transformer
    2. A Pi-network
    3. A length of transmission line
    4. All these choices are correct
    Show answer

    D. All these choices are correct

  11. G5A11 What letter is used to represent reactance?

    1. Z
    2. X
    3. B
    4. Y
    Show answer

    B. X

  12. G5A12 What occurs in an LC circuit at resonance?

    1. Current and voltage are equal
    2. Resistance is cancelled
    3. The circuit radiates all its energy in the form of radio waves
    4. Inductive reactance and capacitive reactance cancel
    Show answer

    D. Inductive reactance and capacitive reactance cancel

G5B

  1. G5B01 What dB change represents a factor of two increase or decrease in power?

    1. Approximately 2 dB
    2. Approximately 3 dB
    3. Approximately 6 dB
    4. Approximately 9 dB
    Show answer

    B. Approximately 3 dB

  2. G5B02 How does the total current relate to the individual currents in a circuit of parallel resistors?

    1. It equals the average of the branch currents
    2. It decreases as more parallel branches are added to the circuit
    3. It equals the sum of the currents through each branch
    4. It is the sum of the reciprocal of each individual voltage drop
    Show answer

    C. It equals the sum of the currents through each branch

  3. G5B03 How many watts of electrical power are consumed if 400 VDC is supplied to an 800-ohm load?

    1. 0.5 watts
    2. 200 watts
    3. 400 watts
    4. 3200 watts
    Show answer

    B. 200 watts

  4. G5B04 How many watts of electrical power are consumed by a 12 VDC light bulb that draws 0.2 amperes?

    1. 2.4 watts
    2. 24 watts
    3. 6 watts
    4. 60 watts
    Show answer

    A. 2.4 watts

  5. G5B05 How many watts are consumed when a current of 7.0 milliamperes flows through a 1,250-ohm resistance?

    1. Approximately 61 milliwatts
    2. Approximately 61 watts
    3. Approximately 11 milliwatts
    4. Approximately 11 watts
    Show answer

    A. Approximately 61 milliwatts

  6. G5B06 What is the PEP produced by 200 volts peak-to-peak across a 50-ohm dummy load?

    1. 1.4 watts
    2. 100 watts
    3. 353.5 watts
    4. 400 watts
    Show answer

    B. 100 watts

  7. G5B07 What value of an AC signal produces the same power dissipation in a resistor as a DC voltage of the same value?

    1. The peak-to-peak value
    2. The peak value
    3. The RMS value
    4. The reciprocal of the RMS value
    Show answer

    C. The RMS value

  8. G5B08 What is the peak-to-peak voltage of a sine wave with an RMS voltage of 120 volts?

    1. 84.8 volts
    2. 169.7 volts
    3. 240.0 volts
    4. 339.4 volts
    Show answer

    D. 339.4 volts

  9. G5B09 What is the RMS voltage of a sine wave with a value of 17 volts peak?

    1. 8.5 volts
    2. 12 volts
    3. 24 volts
    4. 34 volts
    Show answer

    B. 12 volts

  10. G5B10 What percentage of power loss is equivalent to a loss of 1 dB?

    1. 10.9 percent
    2. 12.2 percent
    3. 20.6 percent
    4. 25.9 percent
    Show answer

    C. 20.6 percent

  11. G5B11 What is the ratio of PEP to average power for an unmodulated carrier?

    1. 0.707
    2. 1.00
    3. 1.414
    4. 2.00
    Show answer

    B. 1.00

  12. G5B12 What is the RMS voltage across a 50-ohm dummy load dissipating 1200 watts?

    1. 173 volts
    2. 245 volts
    3. 346 volts
    4. 692 volts
    Show answer

    B. 245 volts

  13. G5B13 What is the output PEP of an unmodulated carrier if the average power is 1060 watts?

    1. 530 watts
    2. 1060 watts
    3. 1500 watts
    4. 2120 watts
    Show answer

    B. 1060 watts

  14. G5B14 What is the output PEP of 500 volts peak-to-peak across a 50-ohm load?

    1. 8.75 watts
    2. 625 watts
    3. 2500 watts
    4. 5000 watts
    Show answer

    B. 625 watts

G5C

  1. G5C01 What causes a voltage to appear across the secondary winding of a transformer when an AC voltage source is connected across its primary winding?

    1. Capacitive coupling
    2. Displacement current coupling
    3. Mutual inductance
    4. Mutual capacitance
    Show answer

    C. Mutual inductance

  2. G5C02 What is the output voltage if an input signal is applied to the secondary winding of a 4:1 voltage step-down transformer instead of the primary winding?

    1. The input voltage is multiplied by 4
    2. The input voltage is divided by 4
    3. Additional resistance must be added in series with the primary to prevent overload
    4. Additional resistance must be added in parallel with the secondary to prevent overload
    Show answer

    A. The input voltage is multiplied by 4

  3. G5C03 What is the total resistance of a 10-, a 20-, and a 50-ohm resistor connected in parallel?

    1. 5.9 ohms
    2. 0.17 ohms
    3. 17 ohms
    4. 80 ohms
    Show answer

    A. 5.9 ohms

  4. G5C04 What is the approximate total resistance of a 100- and a 200-ohm resistor in parallel?

    1. 300 ohms
    2. 150 ohms
    3. 75 ohms
    4. 67 ohms
    Show answer

    D. 67 ohms

  5. G5C05 Why is the primary winding wire of a voltage step-up transformer usually a larger size than that of the secondary winding?

    1. To improve the coupling between the primary and secondary
    2. To accommodate the higher current of the primary
    3. To prevent parasitic oscillations due to resistive losses in the primary
    4. To ensure that the volume of the primary winding is equal to the volume of the secondary winding
    Show answer

    B. To accommodate the higher current of the primary

  6. G5C06 What is the voltage output of a transformer with a 500-turn primary and a 1500-turn secondary when 120 VAC is applied to the primary?

    1. 360 volts
    2. 120 volts
    3. 40 volts
    4. 25.5 volts
    Show answer

    A. 360 volts

  7. G5C07 What transformer turns ratio matches an antenna’s 600-ohm feed point impedance to a 50-ohm coaxial cable?

    1. 3.5 to 1
    2. 12 to 1
    3. 24 to 1
    4. 144 to 1
    Show answer

    A. 3.5 to 1

  8. G5C08 What is the equivalent capacitance of two 5.0-nanofarad capacitors and one 750-picofarad capacitor connected in parallel?

    1. 576.9 nanofarads
    2. 1,733 picofarads
    3. 3,583 picofarads
    4. 10.750 nanofarads
    Show answer

    D. 10.750 nanofarads

  9. G5C09 What is the capacitance of three 100-microfarad capacitors connected in series?

    1. 0.33 microfarads
    2. 3.0 microfarads
    3. 33.3 microfarads
    4. 300 microfarads
    Show answer

    C. 33.3 microfarads

  10. G5C10 What is the inductance of three 10-millihenry inductors connected in parallel?

    1. 0.30 henries
    2. 3.3 henries
    3. 3.3 millihenries
    4. 30 millihenries
    Show answer

    C. 3.3 millihenries

  11. G5C11 What is the inductance of a circuit with a 20-millihenry inductor connected in series with a 50-millihenry inductor?

    1. 7 millihenries
    2. 14.3 millihenries
    3. 70 millihenries
    4. 1,000 millihenries
    Show answer

    C. 70 millihenries

  12. G5C12 What is the capacitance of a 20-microfarad capacitor connected in series with a 50-microfarad capacitor?

    1. 0.07 microfarads
    2. 14.3 microfarads
    3. 70 microfarads
    4. 1,000 microfarads
    Show answer

    B. 14.3 microfarads

  13. G5C13 Which of the following components should be added to a capacitor to increase the capacitance?

    1. An inductor in series
    2. An inductor in parallel
    3. A capacitor in parallel
    4. A capacitor in series
    Show answer

    C. A capacitor in parallel

  14. G5C14 Which of the following components should be added to an inductor to increase the inductance?

    1. A capacitor in series
    2. A capacitor in parallel
    3. An inductor in parallel
    4. An inductor in series
    Show answer

    D. An inductor in series

Questions: NCVEC Question Pool Committee (public domain). Pool valid July 1, 2023 – June 30, 2027.