FCC General Exam Question Pool. Subelement 3BE. Electrical Principals. 2 Questions. -------------------------------------------------- 3E 1.1 C What is meant by the term IMPEDANCE? A. The electrical charge stored in a Capacitor. B. The opposition to the flow of AC in a circuit containing only Capacitance C. The opposition to the flow of AC in a circuit. D. The force of repulsion presented to an electric field with the same charge. 3E 1.2 C What is the opposition to the flow of AC in a circuit containing both resistance and reactance called? A. Ohm. B. Joule. C. Impedance. D. Watt. 3E 3.1 B What is meant by the term REACTANCE? A. Opposition to DC caused by Resistors. B. Opposition to AC caused by Inductors and Capacitors. C. A property of ideal Resistors in AC circuits. D. A large spark produced at switch contacts when an Inductor is de-energized. 3E 3.2 D What is the opposition to the flow of AC caused by Inductor called? A. Resistance. B. Reluctance. C. Admittance. D. Reactance. 3E 3.3 D What is the opposition to the flow of AC caused by Capacitor called? A. Resistance. B. Reluctance. C. Admittance. D. Reactance. 3E 3.4 D How does a coil react to AC? A. As the frequency of the applied AC increases, the reactance decreases. B. As the amplitude of the applied AC increases, the reactance also increases. C. As the amplitude of the applied AC increases, the reactance decreases. D. As the frequency of the applied AC increases, the reactance also increases. 3E 3.5 A How does a Capacitor react to AC? A. As the frequency of the applied AC increases, the reactance decreases. B. As the frequency of the applied AC increases, the reactance increases. C. As the amplitude of the applied AC increases, the reactance also increases. D. As the amplitude of the applied AC increases, the reactance decreases. 3E 6.1 A When will a power source deliver maximum output? A. When the impedance of the load is equal to the impedance of the source. B. When the SWR has reached a maximum value. C. When the power supply fuse rating equals the primary winding current. D. When air wound transformers are used instead of iron core transformers. 3E 6.2 D What is meant by IMPEDANCE MATCHING? A. To make the load impedance much greater than the source impedance. B. To make the load impedance much less than the source impedance. C. To use a Balun at the antenna feed point. D. To make the load impedance equal to the source impedance. 3E 6.3 D What occurs when the Impedance of an electrical load is equal to the internal impedance of the power source? A. The source delivers minimum power to the load. B. There will be a high SWR condition. C. No current can flow through the circuit. D. The source delivers maximum power to the load. 3E 6.4 A Why is IMPEDANCE MATCHING important in radio work? A. So the source can deliver maximum power to the load. B. So the load can draw minimum power from the source. C. To ensure that there is less resistance than reactance in the circuit. D. To ensure that the resistance and reactance in the circuit are equal. 3E 7.2 B What is the unit measurement of Reactance? A. Mho. B. Ohm. C. Ampere. D. Siemen. 3E 7.4 A What is the unit measurement of Impedance? A. Ohm. B. Volt. C. Ampere. D. Watt. 3E 10.1 A What is a BEL? A. The basic unit used to describe a change in power levels. B. The basic unit used to describe a change in inductances. C. The basic unit used to describe a change in capacitances D. The basic unit used to describe a change in resistances. 3E 10.2 A What is a DECIBEL. A. A unit used to describe a change in power levels equal to 0.1 bel. B. A unit used to describe a change in power levels equal to 0.01 bel. C. A unit used to describe a change in power levels equal to 10 bels. D. A unit used to describe a change in power levels equal to 100 bels. 3E 10.3 D Under ideal conditions, a barely detectable change in loudness is approximately how many dB? A. 12 dB. B. 6 dB. C. 3 dB. D. 1 dB. 3E 10.4 B A two times increase in power results in a change of how may dB? A. Multiplying the original power by 2 gives a new power that is 1 dB higher. B. Multiplying the original power by 2 gives a new power that is 3 dB higher. C. Multiplying the original power by 2 gives a new power that is 6 dB higher. D. Multiplying the original power by 2 gives a new power that is 12 dB higher. 3E 10.5 D An increase of 6 dB results from raising the power by how may times? A. Multiply the original power by 1.5 to get the new power. B. Multiply the original power by 2 to get the new power. C. Multiply the original power by 3 to get the new power. D. Multiply the original power by 4 to get the new power. 3E 10.6 B A decrease of 3 dB results from lowering the power by how may times? A. Divide the original power by 1.5 to get the new power. B. Divide the original power by 2 to get the new power. C. Divide the original power by 3 to get the new power. D. Divide the original power by 4 to get the new power. 3E 10.7 C A signal strength report is "10dB over S9". If the transmitter power is reduce from 1500 Watts to 150 watts, what should be the new signal strength report? A. S5 B. S7 C. S9 D. S9 plus 5dB 3E 10.8 D A signal strength report is "20dB over S9". If the transmitter power is reduce from 1500 Watts to 150 watts, what should be the new signal strength report? A. S5 B. S7 C. S9 D. S9 plus 10dB 3E 10.9 C A signal strength report is "20dB over S9". If the transmitter power is reduce from 1500 Watts to 15 watts, what should be the new signal strength report? A. S5 B. S7 C. S9 D. S9 plus 5dB 3E 12.1 D If a 1.0 ampere current source is connected to two parallel connected 10 ohm Resistors, how much current passes through each Resistor? A. 10 amperes. B. 2 amperes. C. 1 ampere. D. 0.5 ampere. 3E 12.3 B In a parallel circuit with a voltage source and several branch Resistors, what relationship does the total current have to the branch currents? A. The total equals the average of the branch current in each Resistor. B. The total equals the sum of the branch currents in each Resistor. C. The total decreases as more parallel Resistors are added to the circuit. D. The total is calculated by adding the voltage drops across each Resistor and multiplying the sum by the total number of all circuit Resistors. 3E 13.1 B How many Watts of electrical power are being dissipated when a 400 VDC power source supplies an 800 Ohm load? A. 0.5 Watt is dissipated. B. 200 Watts are dissipated. C. 400 Watts are dissipated. D. 320,000 Watts are dissipated. 3E 13.2 D How many Watts of electrical power are being consumed by a 12 VDC pilot light which dwaws 0.2 Amperes? A. 60 watts. B. 24 watts. C. 6 watts. D. 2.4 watts. 3E 13.3 A How many Watts are being dissipated when 7.0 miliamperes flows through 1.25 Kilohms? A. Approximately 61 milliwatts. B. Approximately 39 milliwatts. C. Approximately 11 milliwatts. D. Approximately 9 milliwatts. 3E 14.1 C How is the total resistance calculated calculated for several Resistors in series? A. The total resistance must be divided by the number of Resistors to ensure accurate measurement of resistance. B. The total resistance is always the lowest-rated resistance. C. The total resistance is found by adding the individual resistances together. D. The tolerance of each Resistor must be raised proportionally to the number of Resistors. 3E 14.2 D What is the total resistance of two equal, parallel connected Resistors? A. Twice the sum of either resistance? B. The sum of the two resistances. C. The total resistance cannot be determined without knowing the exact resistances. D. Half the resistance of either Resistor. 3E 14.3 A What is the total inductance of two equal, parallel connected Inductors? A. Half the inductance of either Inductor, assuming no mutual inductance. B. Twice the inductance of either Inductor, assuming no mutual inductance. C. The sum of the two Inductances, assuming no mutual inductance. D. The total inductance cannot be determined without knowing the exact inductances. 3E 14.4 B What is the total capacitance of two equal, parallel connected Capacitors? A. Half the capacitance of either Capacitor. B. Twice the capacitance of either Capacitor. C. The value of either Capacitor. D. The total capacitance cannot be determined without knowing the exact capacitances. 3E 14.5 B What is the total resistance of two equal, series connected Resistors? A. Half the resistance of either Resistor. B. Twice the resistance of either Resistor. C. The value of either Resistor. D. The total resistance cannot be determined without knowing the exact resistances. 3E 14.6 B What is the total inductance of two equal, series connected Inductors? A. Half the inductance of either Inductor, assuming no mutual coupling. B. Twice the inductance of either Inductor, assuming no mutual coupling. C. The value of either Inductor, assuming no mutual coupling. D. The total inductance cannot be determined without knowing the exact inductances. 3E 14.7 A What is the total capacitance of two equal, series connected Capacitors? A. Half the capacitance of either Capacitor. B. Twice the capacitance of either Capacitor. C. The value of either Capacitor. D. The total capacitance cannot be determined without knowing the exact capacitances. 3E 15.1 C What is the voltage across a 500 turn secondary winding in a transformer when the 2250 turn primary is connected to 117 VAC? A. 2369 volts. B. 526.5 volts C. 26 volts D. 5.8 volts 3E 15.2 A What is the turns ratio of a transformer to match an audio amplifier having an output impedance of 200 ohms to a speaker having a load impedance of 10 ohms? A. 4.47 to 1. B. 14.14 to 1. C. 20 to 1. D. 400 to 1. 3E 15.3 A What is the turns ratio of a transformer to match an audio amplifier having an output impedance of 600 ohms to a speaker having a load impedance of 4 ohms? A. 12.2 to 1. B. 24.4 to 1. C. 150 to 1. D. 300 to 1. 3E 15.4 D What is the impedance of a speaker which requires a transformer with a turns ratio of 24 to 1 to match an audio amplifier having an output impedance of 2000 Ohms? A. 576 ohms. B. 83.3 ohms. C. 7.0 ohms. D. 3.5 ohms. 3E 16.1 B What is the voltage that would produce the same amount of heat over time in a resistive element as would an applied sine wave ac voltage? A. A DC voltage equal to the Peak To Peak value of the AC voltage. B. A DC voltage equal to the RMS value of the AC voltage. C. A DC voltage equal to the Average value of the AC voltage. D. A DC voltage equal to the Peak value of the AC voltage. 3E 16.2 D What is the peak-to-peak voltage of a sine wave which has an RMS voltage of 117 volts? A. 82.7 volts. B. 165.5 volts. C. 183.9 volts. D. 330.9 volts. 3E 16.3 B A sine wave of 17 Volts Peak is equivalent to how many Volts RMS? A. 8.5 volts. B. 12 volts. C. 24 volts. D. 34 volts. -------------------------------------------------- End of Subelement 3BE.