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General Class Exam Question Pool

effective 7/01/2015 thru 6/30/2019

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2015-G5A: Reactance; inductance; capacitance; impedance; impedance matching

2015-G5A01: What is impedance?

The opposition to the flow of current in an AC circuit

The electric charge stored by a capacitor

The inverse of resistance

The force of repulsion between two similar electric fields



2015-G5A02: What is reactance?

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

Opposition to the flow of direct current caused by resistance

A property of ideal resistors in AC circuits

A large spark produced at switch contacts when an inductor is de-energized



2015-G5A03: Which of the following causes opposition to the flow of alternating current in an inductor?

Reactance

Conductance

Reluctance

Admittance



2015-G5A04: Which of the following causes opposition to the flow of alternating current in a capacitor?

Reactance

Conductance

Reluctance

Admittance



2015-G5A05: How does an inductor react to AC?

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

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

As the amplitude of the applied AC increases, the reactance increases

As the amplitude of the applied AC increases, the reactance decreases



2015-G5A06: How does a capacitor react to AC?

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

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

As the amplitude of the applied AC increases, the reactance increases

As the amplitude of the applied AC increases, the reactance decreases



2015-G5A07: What happens when the impedance of an electrical load is equal to the output impedance of a power source, assuming both impedances are resistive?

The source can deliver maximum power to the load

The source delivers minimum power to the load

The electrical load is shorted

No current can flow through the circuit



2015-G5A08: Why is impedance matching important?

So the source can deliver maximum power to the load

So the load will draw minimum power from the source

To ensure that there is less resistance than reactance in the circuit

To ensure that the resistance and reactance in the circuit are equal



2015-G5A09: What unit is used to measure reactance?

Ohm

Farad

Ampere

Siemens



2015-G5A10: What unit is used to measure impedance?

Ohm

Volt

Ampere

Watt



2015-G5A11: Which of the following describes one method of impedance matching between two AC circuits?

Insert an LC network between the two circuits

Reduce the power output of the first circuit

Increase the power output of the first circuit

Insert a circulator between the two circuits



2015-G5A12: What is one reason to use an impedance matching transformer?

To maximize the transfer of power

To minimize transmitter power output

To reduce power supply ripple

To minimize radiation resistance



2015-G5A13: Which of the following devices can be used for impedance matching at radio frequencies?

All of these choices are correct

A transformer

A Pi-network

A length of transmission line





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General Class Exam Question Pool
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2015-G5B: The Decibel; current and voltage dividers; electrical power calculations; sine wave root-mean-square (RMS) values; PEP calculations
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